A lot of it comes down to how you design your ships. They need to be designed with a certain philosophy and then set to tactics appropriate to their equipment. Some available roles in DW, in my experience:
* Long range combatant ("Archer"). Decent speed & turning, designed to always engage at long range with velocity torpedoes or missiles. Can often get away with inferior shielding. Good at spaceport sieges, and against ancient vessels in the early-mid game. (Won't work on Shakturi owing to their armor!) This design philosophy is excellent for Escorts.
* Tackler. This is a ship optimized for short range combat & mounting a hyper deny module. Usually cheap enough to be expandable. It doesn't have to be particularly fast but is better at its job if it is. This ship keeps enemy vessels in combat. It can be a good idea for them to emphasize defense over firepower, depending on your technology and philosophy.
* Slugger. This ship sacrifices speed for extreme armament & shielding for its size. It's designed to win fights - nothing more, nothing less. The primary flaw of this design tends to actually be logistical; slow ships are PAINFULLY slow at refueling or repairing at spacedock, especially when low on gas! I tend not to use this design for that reason, unless my ships simply cannot match the enemy.
* Warship. Generalist design that is designed to be adaptable. It mounts both long and short range weapons so that it can use the best weapons for a particular ship design. It needs to have a reasonable turn of speed so that it can be certain that it is choosing the engagement range.
* Pirate Escort. Pirate Escorts are a special case. When the AI is managing them they function as independent raiders, so they need to be designed with that in mind unlike empire escorts. Good speed is paramount so they can reach planets and deliver their raiders, and you want firepower so they can down enemy shields for boarding.
* Psycho. These ships close to point blank range in all circumstances. This is good for railgun ships for obvious reasons, but is extremely dangerous. Impact Assault Blasters also benefit from this.