Dogfighting

Lead your shots
Explained why quite well here. Applies to all forms of combat. The lead needs to be from .5-1 second in the direction of motion for autoaim to kick in.



In the above image you can see the one seemingly stray shot; that shot is indicating that you're autoaiming at the actual enemy mech. The shot looks like it's outside the normal autoaim cone (blue area), but it is in fact within the actual cone. This is merely the graphical representation that you're firing at the mech. The actual mech you want to hit will be the red outline within the firing cone.

This can be difficult and counterintuitive, because you will aim at seemingly empty space at times, but it does work if you do it right. Lead shots by 1-1.5-2 mech lengths depending on the mech speed and autoaim will do the rest.

Rotation


Due to the above lag phenomena along with limited rotation speed of mechs while firing, it is ill advised to keep still during combat. Always position your self at optimal range from the enemy, preferably in their blind spot. It is difficult to fine at an enemy that is moving rapidly around you, take advantage of that. You can confuse the enemy by running straight though him and then firing while he's reorienting, while continuing to move around.

To counter someone running circles around you, you can either land and try to juke away, or gain a better firing position by backing away and catching them in the now wider firing cone.

You rotate faster, the more distance you have to rotate while firing. So if you start firing behind you, the initial rotational speed will be greater than if you needed to fire left/right. You can try taking advantage of that to aim faster. As far as I can tell, mech speed modifiers do affect mech rotation speed during firing slightly. So you will have more trouble hitting mechs using Beppo as opposed to Raven. The effect isn't all that huge though.

Running
There are several ways to run away from death, and each one is highly situational. But usually, staying alive is much much better than dying. Unless the cost of staying and fighting is higher than living, don't banzai into things.

Fighting Retreat


Use this when your life isn't in much danger, but the enemy wants to give chase. Deter the chase by facing the enemy and firing as you back away. Sometimes can even be used as a lure.

Run For Your Life


When you don't have enough health to fight back. If all else fails, try to bolt out of there. If the enemy is hovering over you preventing escape, start walking away. If you can trick him into landing, the delay before he can lift off again should be enough to run away safely. If you're out of energy...well, that sucks, bro.

Juking


The pinnacle of fleeing techniques: Juking. When the enemy is chasing you, your health is low and you're far from friendly forces, land and walk towards your base. If it's only one enemy, he will likely try to land to finish you off. At this point, lift off and try to run. If the enemy lifts off again and you think he'll be able to kill you, land again and keep walking. Rinse and repeat til you reach friendly territory. If you can, use cover, such as outposts and rocks. Note: Watch out for cliff jumping, your reflexes to lift off might work against you these situations.

Harass


Make your enemy nervous about leaving their outpost while also keeping an eye on them. Harass them over their outpost. While this won't land any kills, it is rather good if you have nothing better to do. If you can get your friend(s) to help out, with a bit of luck you can actually kill mechs over outposts.



When you see the enemies engaged on a front, odds are they're not paying attention to their base or their minimap. Use this opportunity to wreak some serious havok. When you see them return, do not overextend unless you're really sure it's worth it. Better to bolt to fight another day.

Rolling Cover
Always try to fight with unit support. If you're getting shot at, use your units for cover. Your mech has the higher DPS than any unit, but not enough HP to tank all the damage. It is usually much more beneficial to let the units take the beating while you blast the enemy.

Mech Fighting
Fighting ground mechs is problematic because they're so fast. But the good thing about groundfighting is that there is no rotation speed limit, you will fire in the direction you point instantly. The lag phenomena makes aiming difficult though. So I'd recommend using autoaim against grounded mechs. If you have bombs, vertical fire or missiles, use those to prevent easy escapes.

Cliff Jumping
There is a technique you can perform to land, do some damage and then lift off without the usual delay. It works up to a second after you land. Just land near a cliff and then walk off it. This will turn you back into plane mode instantly. You can use this when chasing and when juking. Watch out when others do it to you when you're trying to run.

Autoaim
I know some of you guys think of it as cheating, but that's silly. It's part of the game now, and as such should be used where applicable.

Autoaim does a great job tracking landmechs in close quarters. Even with the damage penalty, it is well worth it to use it against ground mechs, since 80% damage 100% of the time is way better than 100% damage 30% of the time.

Autoaim is also great for close quarter air fighting where it's impossible to tell the real position of the enemy mech. Use autoaim until you can use normal fire. Switch between normal fire and autoaim as necessary for maximal effect.

Binding Autoaim to an easily accessible key like Ctrl, or extra mouse buttons if you have them makes it much more useable.

Controller
Controller allows analog control of your flight paths, generally allowing you to fly in a straighter path to your destination vs the switching between principal directions on KBM. Controller also has a larger firing autoaim cone. Some argue that it is also a lot more comfortable since all functions of a mech are easily reachable and abilities are easier to activate than the obnoxious middle click.

Team Fighting


If you see your teammate is getting double teamed, go help him. You might not get any kills, but at least you can help him get away from an otherwise horrible and inevitable death.



If you see an isolated enemy on the ground, double team him. One of you stays in the air preventing escape, while the other goes on the ground and butchers him. Also helps to prevent surprise attacks by the enemy where instead you would be double teamed if you solo.