It's a well known fact among RPers, at least Star Wars ones, that space battles are not easy things to do in a text-based RP. The most common reason is that unlike a land battle, they have three dimensions. Land battles, of course, have ships too, but not in the same numbers as a space battle. This tutorial, hopefully, will make your next full-scale space RP a little easier.
1. Get used to using three dimensions.
I can't stress this enough - having three dimensions to fight in makes things a whole lot more complicated. In a land fight, you've just got one plane. In space, there's an infinite number of planes to go to. You're not limited by sky or ground. What I notice a lot of people doing is just using that one plane; for instance, when in a battle where an attacker is going for a planet, the defenders move a unit of ships to block. But, the defenders don't say they're using a screen - they're assembled in a line. More often than not, the attackers simply try to break through when a simple dive under their line would make things much easier.
Of course, if the attackers were going for a specific point on the planet a dive wouldn't work, but you could use a dive and climb split, where a unit of ships moves straight at the defending line, then branches off with one unit moving up and above the enemy while the other goes under. The defenders have to maneuver to get the bulk of their firepower aimed at the lower ships, as the underside usually has the least heavy armament, which leaves the upper ships open to fire on the undersides of the defending ships.
For the most part, space battles are a matter of manipulating the third dimension - elevation. Once you can do that, you're golden.
2. Manage your capital ships like capital ships and fighters like fighters.
Another thing I see that annoys me quite a bit is when people use their capital ships and fighters together, saying, "The capital ships move through the opening with the fighters." This, for one, is just about impossible, unless the fighters were moving at the same pace. The thing is, capital ships like Star Destroyers are much slower realistically than fighters.
This is actually a good thing; you can use fighters to harass large ships, as the main guns of a Star Destroyer are just about ineffective against fighters, while your capital ships move in to deliver the heavy weapons to destroy enemy capital ships. You have to learn to move them independently and not bunch them into one movement.
3. Practice by using a visual reference.
Basically, this just means play a game that has a visual element and takes place in space. There's tons of examples, such as Wing Commander, Dark Star One, Spaceforce 2: Rogue Universe, or any of the Wing Commander games. My personal recommendation though is to get your hands on any Homeworld game. A RTS set in space, in Homeworld you'll use a variety of ships ranging from probes to destroyers and carriers, all on that critically important three dimensional plane. Star Wars: Empire at War is okay, but it's space battles are flat and don't have a depth element to them. This is where Homeworld'll prove to be great practice material.
I know this isn't a whole lot of tips, but participating in a space battle isn't truly difficult. It just takes breaking into that elevation dimension and changing your RP command style to accomodate. Playing Homeworld or some space sim will help with this, so you get a feel for attacking the undefended or lightly defended sides of an enemy and using pincer attacks from above and below.
I hope this helps you all, thanks for reading.