Dimension Style

The Dimension Style screen is used to set everything related to dimensioning in your drawing.  If you change an option here, it will apply to all the dimensioning in your drawing. 

Under the text tab, shown to the right, you can change the dimension text size, as well as color and line weight and other similar options.  Only change the text size in the Dimension Styles window though, as it is best to change the other options in the Layer Properties window.

You can also change the text alignment and orientation which will effect what the dimensions look like as they are placed on the drawing.  In general, these options are not changed often, except text size.

 
Under the Primary Units tab, we can change the precision that our dimensions go out to.  The default four zeros (0.0000).  This is often way more precise than we would need for our drawings, so you can change the precision down to one or two, or whatever the drawing guidelines specify.

Angular precision is set to the nearest integer (nothing after the decimal).  If you wish to make angular dimensions more precise, you can do this in this window also.

Lastly, you may wish to turn off extra zeroes in your drawing.  Instead of having a dimension of 1/2" being 0.50, you can turn off the leading zero and have it read .50.  This is under the Zero Suppression area of this window.  You can also suppress trailing zeros, which would turn 2.50 into 2.5.  Usually you want to leave trailing zeroes on because it shows that the dimension is accurate out to that decimal place.