Concerning stealth and space combat:
http://www.projectrho.com/rocket/
especially under "common misconceptions", then look for "stealth"
--> http://www.projectrho.com/rocket/rocket3w.html#nostealth
I'm aware that
stealth in space is difficult to pull off, but by "ECM", I didn't meant just stealth.
Electronic Counter Measures can include: absorption or deflection of waves used by sensors (main concept of stealth), screening, decoys, noise emitters (they saturate space with various signals that have no meaning and make detection difficult), maybe even interference jamming (emitting EM waves which cancel out waves emitted by ships by destructive interference, this is likely to by used by really advanced aliens). Combining several ECM measures with tactics like hiding close to planets and asteroids would greatly reduce reliability of ship sensors.
You may know that the enemy is there, but pinpointing him may be a problem. You need to have exact coordinates to fire a beam (unless you're slashing and praying for lucky shot) and missiles can be shot down, so bombers may be usefull to bring those missiles close to enemy ships and fighters to defend against bombers.
My entire statement assumed that you may use jamming good enough to keep the enemy from pinpointing you and that both sides have access to it.
An idea that the enemy is "somewhere about 100km from there, roughly in that direction" isn't going to be enough when firing weapons.
Also, tactics may really vary considering the weapons themselves, a laser beam can be reflected, gamma beam is an energy hog, missiles may be shot down, remote controll can be jammed, AI may be just stupid (it it's not, it may be too inteligent and realize it's going to "die")...
In fact, the only way of finding out how future space battles will look would be to take a trip into future (if we will be lucky, even this may not help, as humanity may abandon warfare at all in the future, or, if we are unlucky, become extinct due to weapons we already have).