Having played a few games now I am understanding this game better and better. One of the mechanic that is new to me is the concept of activation. What happens is a player take one squadron to activate, which includes movement, shooting, and boarding. Once a squadron has completed its activation, no further offensive action can come from the squadron this turn. In each turn, activation alternates between players. So the question is what to activate first. My rules for activation order are as follow.
I. Massive model first. Models like dreadnoughts class models are most durable to resist return fire. As you move your massive model forward, it will attract attention from your opponent so take advantage of this. Large and massive models will have longer ranged weapon thus will also be better to attack with when the enemy may still be further away and out of reach of most of your forces. Among options with reach, activate damaged squadron before undamaged model. If your model is damaged, your opponent will want to kill it so use it while you still can.
II. Large model next. Longer ranged weapon battleship before damaged squadron.
III. Medium model squadron next. Longer ranged weapon before damaged squadron.
IV. Small model squadron next. Longer ranged weapon before damaged squadron.
V. Tiny flyer squadron last. Thing is damaged model will also lose AA, so will be easier targets for your tiny models. When you have both fighters and tiny bombers, the fighters should act before the bombers to take out enemy fighters. If enemy fighters are not within reach, then take out enemy bombers. However, if the tiny bombers can strike a desired target, then take the action when you can. If you have no tiny bombers deployed, then the fighters should selectively target enemy bombers, tiny or otherwise.
VI. Carriers last. Carriers are not gunships, just to coordinate and support tiny flyer squadrons.