Sometimes it is necessary to change the colors and symbols in your map to improve its ability to communicate spatial information. You can change the color, symbols, and shadings used to draw a theme.
Uncheck all the themes in the Table of Contents except for the theme "Uganda_district.shp." Right now on my computer the color representing the districts is light blue.
We want to change the color used to illustrate "Uganda_district.shp" on our map, a very simple task.
Double-click right on the theme name "Uganda_district.shp" in the Table of Contents to bring up the Legend Editor dialog box. 
In the Legend Editor dialog box, you will see the heading "Symbol" on the left side. Below the word "Symbol" is a light blue-colored rectangle; the rectangle is light blue because that is the color that is now used to represent the theme "Uganda_district.shp" in our map. Now double-click on the light blue rectangle. This will enable us to change the color for "Uganda_district.shp" from light blue to another color.
The Fill Palette window will now appear over the Legend Editor dialog box.
(Note: I widened the small Palette window so that you can see it more clearly.)
Note that there are six icons across the top of this small window, the first representing the Fill Palette (which is now visible). The tools associated with these six icons across the top of this palette can be used to alter the colors, symbols, and text used to represent a theme on a map.
In the Fill Palette window, you can change the patterns within polygons drawn on the map.
Notice that the black solid square in the middle of the first row of symbols is highlighted by a square around it, which indicates that we are using a solid fill pattern (in this case, solid light blue) to represent our theme "Uganda_district.shp" on our map.
To change the color of the fill pattern, click on the fifth icon from the left at the top of the Palette window, which looks like a paintbrush. 
It brings up the Color Palette window.
Here you can change the color that you use to represent our theme.
Notice that next to the word "Color:" is a drop-down list. The current choice is "Foreground" which indicates that you want to change the foreground color of a polygon, line, or point--in this case the polygon representing "Uganda_district.shp."
Click on the color "light red," which will produce a black outline around the light red color chosen in the window.
Note also that the rectangle below "Symbol" in the Legend Editor dialog box has also changed to the light red color that we have chosen.
Now click on the Apply button at the bottom right of the Legend Editor dialog box and close both the Color Palette window and the Legend Editor dialog box. Your map should look like this with the new color displayed.
What if you want to display two polygon themes of the same place at the same time?
We will do this with two polygon themes. One represents soil types. The other represents parcels of land in which people grow their crops.
First add the theme "Uga_soil.shp" (a map of Uganda soils) and then add the theme "shambas.shp" (a map that I created of the boundaries of parcels of land used for growing crops in the Iganga area) so that "shambas.shp" appears above "Uga_soil.shp" in the Table of Contents. Display only these two themes in our View. Make the theme "shambas.shp" active and zoom to this active theme. You View should look like this. 
Both themes cannot have solid fill patterns if we want to view their relationship. One solution is to change the fill pattern of "shambas.shp" from a solid fill pattern to a transparent fill pattern.
Double-click on the theme name "shambas.shp" in the Table of Contents to bring up the Legend Editor dialog box and double-click on the colored (here light green) rectangle below the word "Symbol."
The Fill Palette window appears.
Click once on the white square in the top row to the left of the black solid square so that it is highlighted by the outline around it.
This choice replaces the solid fill pattern with a clear fill pattern. Notice that the light green color in the small rectangle in the Legend Editor has also disappeared and is now clear. Close the Fill Palette window, click on the Apply button on the bottom right of the Legend Editor dialog box, and close the Legend Editor dialog box. Your map should look like this.
Because we used a clear fill pattern to portray the "shambas.shp" theme in our View, we can see the underlying map of "Uga_soil.shp" beneath "shambas.shp."
But while we are actually seeing both "Uga_soil.shp" and "shambas.shp" at the same time, it is difficult to discern the boundaries in "Uga_soil.shp" because the lines used to demarcate the boundaries in the two themes appear so similar. We want to make the lines for the boundaries in "Uga_soil.shp" much thicker to see where they are in relation to the boundaries of parcels in "shambas.shp."To do so, double click on the theme name "Uga_soil.shp" in the Table of Contents to bring up the Legend Editor dialog box again and then double-click on the colored (here pink) rectangular box below the word "Symbol" to bring up the Fill Palette window.
Notice at the bottom of the Fill Palette window is the word Outline: and the number "0.1" is in the drop-down list to the right. This number indicates the thickness of the lines used to draw the boundaries of polygons. We want to make the boundaries of polygons in "Uga_soil.shp" appear thicker to reveal their shapes. Click on the down-arrow to reveal the drop-down list and select the number "2" from the list.
Then release the drop-down list. The number "2" should appear next to "Outline."
Note also that the border of the rectangle below the word "Symbol" in the Legend Editor dialog box is now thicker, reflecting the choice that we have made. 
This indicates that if you apply this choice, the lines for boundaries of the polygon will be just as thick as that indicated around the rectangle.
Click on the Apply button on the bottom right of the Legend Editor dialog box and close both the Fill Palette window and the Legend Editor dialog box. Your map should display both themes clearly now. 
This method enables you to display two polygon themes of the same area at the same time.
While we can see the boundaries of both themes clearly at the same time now, a problem remains. How do we see spatial variations in values of the two themes at the same time? In such cases, we cannot use a clear pattern to represent a theme.
We will discuss illustrating spatial variations in values of themes in the next Step, but here we will perform a crucial task. Displaying a theme in a transparent pattern will enable us to see spatial variations within that theme as well as variations in the theme drawn underneath it.
Double-click on the theme name "Shambas.shp" in the Table of Contents to bring up the Legend Editor dialog box and double-click on the rectangle below the word "Symbol" to bring up the "Fill Palette" window.
Then select one of the transparent fill patterns, as I have done.
Then click on the Color Palette button to bring up the Color Palette window.
Then, next to "Color:", change from "Foreground" and select "Background" from the drop-down list. Then click on the box on the far left of the top row with the "X" in it, which is used to represent transparent patterns.
Click on the Apply button in the Legend Editor dialog box and close both the Color Palette window and the Legend Editor dialog box. Your map should look like this:
Now we can see the shadings in "Shambas.shp." Thus, we will be able to illustrate variations in two polygon themes at the same time, when necessary. This is particularly useful when you want to examine and compare the spatial distribution of two polygon themes.
We are now going to use another tool to alter the display of themes--in this case the thickness of lines used to represent themes.
Add the theme "Iganga-river_50000.shp" to the Table of Contents and display it in our View.
Notice that we can hardly see the river in our View, and it is portrayed here in red, whereas it is more appropriate to portray it in blue. Let us make the line representing the river thicker so that the river is easier to see.
Now double-click on the name "Iganga-river_50000.shp" in the Table of Contents to bring up the Legend Editor dialog box.
Notice now that under the word "Symbol" we no longer have a rectangle but a line instead, which represents the line used to depict the theme "Iganga-river_50000.shp" on the map. We want to change both the thickness and color of the line used to represent the rivers.
Double-click on the wavy line in the box below the word "Symbol" to bring up the Pen Palette window. Here you can change both the size and shape of lines. Note that there is a drop-down list for Size at the bottom of the window, which represents the thickness of the line. The current size is "0.1." Click on the down arrow to bring up the drop-down list and select size "2."
Note that the line in the box below the word "Symbol" is now also thicker.
We also want to change the color of the line to deep blue to better represent a river. To change the color, click on the fifth icon from the left at the top of the Pen Palette window to bring up the Color Palette window.
Click on the color blue, which will produce a white outline around the blue color chosen in the window.
Note also that the color of the line in the box below the word "Symbol" in the Legend Editor dialog box has also changed color.
Now click on the Apply button at the bottom right of the Legend Editor dialog box and close both the Color Palette window and the Legend Editor dialog box. Your map should look like this, with the river more clearly displayed.
We can also change the shape, size, and color of point symbols.
Uncheck the boxes next to all the themes in the Table of Contents. Display the theme "Lews_livestock.shp," make it active, and zoom to the active theme so that it is displayed in our View.
Double-click on the theme name "Lews_livestock.shp" in the Table of Contents to bring up the Legend Editor dialog box. We now see a point in the box below the category "Symbol" because we are working with a point theme.
Double-click on the point in the box below the category "Symbol" to bring up the Marker Palette window.
Here you can change both the shape and size of the markers for point themes. Changing the shape, size, and color of markers for points is especially important when you are displaying more than one point theme. Having a different marker shape, marker size, and marker color for each point theme helps you to distinguish among them.
Select a different marker shape in the Marker Palette window by clicking on the shape. I will select a triangular shape.
Note that the shape of the marker also changes in the box below the category "Symbol" in the Legend Editor dialog box.
Now change the size of the marker by clicking on the down-arrow to the right of the category "Size" in the bottom of the window. Select size "16." 
Note that the size of the marker also changes in the box below the category "Symbol" in the Legend Editor dialog box.
Click on the Apply button in the Legend Editor dialog box, close the Legend Editor dialog box, and close the Marker Palette window. Your map should look like this: 
We could also change the color of the marker, just as we did with polygons and lines above.
Here is an example from a different context of using different marker shapes, sizes, and colors for several point themes: 
Note that it is easier to distinguish among the point themes because they are represented by different marker shapes, sizes, and colors.
(Some notes about colors are important. First, it is best not to choose yellow because ArcView uses that color to portray items that you have selected when performing certain types of analyses, as we will discuss in another Step. Second, changing colors is not just for the purpose of being artistic. ArcView randomly chooses colors for themes and sometimes the colors that ArcView produces for two different themes are too similar to be displayed clearly together; in such circumstances it is necessary to change the color of one of the themes.)