This map will be from the perspective of a Terran Republic Player on old Esamir (2019)

Turning on the Heatmap
First things first, turning on the “ENEMY ACTIVITY” or “ALLY + ENEMY ACTIVITY” Heat Map can help to check the population of bases at a glance

Allied Overpop
Ex. Echo Valley Substation

Usually an attack surrounded by friendly vehicles and aircraft, especially if the allied percentage is really high (60% or more). You’ll often only find infantry to kill here, and sometimes it will be as easy as shooting fish in a barrel.

Allied Underpop
Ex. Ymir Southern Reach

Usually a defense surrounded by enemy infantry, vehicles, and/or aircraft. These are the most likely place to find enemy aircraft to kill; but due to enemy AA, you will usually have to get in and out quickly. You can also try luring them away from the fight, and thus away from the AA.

Trying to kill ground targets at these fights is usually a bad idea.

Large Fights
Ex. Eisa Tech Plant

Usually no-fly zones due to the sheer amount of AA. The best you could hope for is picking off vehicles or aircraft at the outskirts of the area, and quickly retreating to repair. 

Trying to kill infantry in the thick of it will be short-lived if you don’t know what you’re doing.

Ex. Andvari Bio Lab

While there’s often not much for aircraft to do here, sometimes there are infantry fighting on the landing pads. You can kill the infantry, or look for enemy aircraft trying to kill the infantry.

3rd-Faction Fights
Ex. Mani Tower

Fights between the two other empires, usually far from your allied territory. Experienced air-to-air players will often fly to these fights when there’s no options elsewhere. High risk, high reward.

High Activity near Enemy Warpgate

If you see a lot of enemy activity at their Warpgate, it’s often outfits preparing to fly out, usually with transports. It’s sometimes an opportunity to pick off the stragglers. Tread carefully.

Sparse Activity near Enemy Warpgate

Sometimes, it’s just enemy ANTs. Other times, they’re aircraft flying from the warpgate that you can pick off. A good place to kill aircraft without constantly taking flak.

Near an Allied Warpgate

While there’s usually nothing, looking here is a good way to find the occasional experienced pilot looking for kills. It’s a good habit to check around whenever you fly out of the Warpgate, whether you want to avoid them or go after them.