General rule: Remove the clutter, high-light the important and sort for quicker use.

I. Let's start with the most basic function. In your overview, click on top of a column to sort your overview. Most common uses are by distance or by name of the pilots. If you're in a fleet with target calling, sorting the targets by name will make it easier to find them on overview. Sorting by distance is what you should use by default.

II. Brackets and overview can be set up separately. Brackets refers to what is shown in space, overview is the window containing your overview. Right-click the small triangle in the top left corner of the overview. Set what you want to see, then save your overview settings. Use a naming convention allowing you to identify settings you want to use for the overview and brackets respectively. (example: drones_ov and drones_br). Now got to the last tab of your overview settings and set up your tabs (name, overview setting, bracket setting).

1) Drones shown on overview have a fantastic ability to clog up your overview. It's preferable to only show them as brackets. Yet in small scale fights or close-up fights you will find it useful to be able to target drones from the overview. Use a specific tab for it that is not your main pvp tab. In some cases it makes sense to not even show drones as brackets, if you feel that they slow your computer down excessively. You have to experiment until you find a useful setup. The escape menu also offers settings to not render drones as complex models, not display turret effects ...

III. Colors and tags, what you ought to know. The second tab on the overview settings allows you to change the colors used as background or for the tags. You can also change whether the colors will flash or not. What is very important to know is that you can change the order of the different states a pilot can have. The top most state which applies will be the only one shown. If you need to see two states simultaneously have one shown by tag and the other one by background. This means that one of both settings needs to follow a different order.

1) Outlaw, but blue. You can set tags to show that a pilot is blue while the background color shows him as outlaw (which by default is a red flashing background).

2) Friend / foe recognition. Remove your fleet members from overview. This is done by unchecking the "pilot is in my fleet" state in the first tab of the overview settings->states. Unfortunately you can't remove neutral ships from overview, as would be useful in high-sec warfare.

IV. In large fleets you may only want to display ships of a certain type / size. For 0.0 pilots it's common to have a tab showing battleships and bigger only. You can select what ships are shown from the first tab in overview settings.

V. Navigation. You can remove stargates from your pvp-overview and set up a tab for navigation, where you only show stargates. This is very useful in low-sec where a quick warp can save a pod.

VI. Columns. The most important info here is that there is a non-labeled column after the last one. Just make sure you have small space after the last labeled column. In this space the overview will display e-war modules that are applied on your ship. You can't have different column settings for different tabs. Most important columns are distance, name and type. Check what other columns are available that could be useful for you. Pilots involved in faction warfare can use the militia column to identify pilots of the allied militia. You can sort the order in which the columns appear by moving them up/down in overview settings.

VII. Switching brackets. As you switch tabs on you overview, both the overview setting and the bracket setting for that tab are loaded. There are additional bracket commands accessible by hot-keys. Hit escape to enter the menu where you can set hot-keys. Hiding all brackets is sometimes used to reduce lag that occurs when you warp to an enemy fleet. Special brackets is the bracket setting you specified for the active overview tab.

VIII. Fleet / solo. The type of fights you expect can change what you need to see on your overview. It can be vital for solo-pilots to display the speed column on the overview.

Experiment and follow the general rule.