Let's do an as exaustive as possible list of what do you need in Space and during a war?
Vital need: The most obvious to begin. I suppose even if you have FTL communication, you won't use only unmaned craft. You will need to provide food and water to your troops. And your ennemy will need supplies to sustain planetary siege you will maybe provoke. Water and food sources as well trade routes (you will probably always use the shortest path, because the voyage without FTL to the closest star is at least 4 years long, see Proxima Centauri) will be real strategic points, if you don't want your troops and population to starve.
Example of water sources: water rich asteroids, frozen moon (like Europa)...
Example of food sources: habitable planet with vegetation and maybe animals, farm spacestation (like in the video game serie X), nebulae (some are believed to contain organic molecules, you could manage to synthetise food with them)...
Military ressources: A bit more specific to war: ammo, spacecraft and fuel. Ammo will be plasma for plasma weapon, ion for ion cannon... Only laser will not need ammo (maybe replacement lens?). You will need to control ammunition factories and be able to supply them (trade routes, again and mines for metals, and various ressources you could need, you will found them in all kind of stellar object, it depend of the nature of the ressources). Same purpose for spacecraft, you need to control "spacedockyard" to be able to repair existing spaceship and building new ones. To fuel for vessels, assuming they are powered by fusion reactor, and not old fashion hydrazine (not efficient enough, too explosive and heavy), you will need hydrogen, to fuel the fusion reaction.
Economy and communication: Money is the sinews of war (and intel too). You will need to control trade routes and "space docks" to destroy the ennemy economy and prevent him to build new spaceship, enroll new troops... To gather intel, controlling ennemy communication and command centers is a good start. They will contain informations and will help you to decypher ennemy code (like with the Enigma machine). 898
It will prevent your ennemy to correctly communicate too, and disorganise his military organisation.
Space specific strategic point: Since the begining, this is the same kind of strategic point than on Earth. Now let's talk about space specific one. A spaceship is really greatly insulate (see vacuum insulated panel). It means your ship will generate many static electricity. It could be dangerous for the ship electronics (and the crew, maybe). You will need to discharge it sometimes if you don't want to be thunderstruck the next time you approach a planet (fun fact, you will be the source of the lightning). You can find this kind of issue with ion thruster (not at the same scale but I assume the activity on your warship will generate static electrecity, firing a ion cannon for example). Heat will be an other problem. You can't dissipate much heat in void, beacause of it's poor thermal conduction (see the begining of the paragraph). You will need to enter a fluid to dissipate heat quickly (a really low temperature liquid is the best of the best). You could dissipate the heat by irradiation to, but you will be really visible (and this is not a good during a war).
Point to discharge static electricity: point with opposite charge like planets or asteroid (if you're lucky)
Point to dissipate heat:where you can find fluids colder than your ship. Ocean on a planet, atmospher of a planet, nebulae...
But on this time and distance scale, war is close to be a none-sense. You could find all the place/ressource you need in another place, closer and more important safer.
I hope you like my list! Thanks for the reading. 898