combat for Infinite Space is pretty much just pick a command, wait for the gauge to fill up and choose the command. But the trick is timing, and sometimes it helps to "kite" too (keeping out of range while waiting for gauge, then moving in to attack and moving out again).
Never fully deplete the gauge, unless it's for dodge/evade.
Learn to watch the opponents' color. This gives you a clue to how far up their gauge is, which tells you what attacks they're most likely to do.
As soon as you see them go red, go into Dodge mode, as they're probably priming for a Barrage or a Special attack. Risk is that the enemy might instead opt to do a bunch of normal attacks-- this will hurt if you're in Dodge mode, and you can only cancel that mode by attacking.
Also, when you see them go red, after going into Dodge mode, save up for a Barrage. This way, if they do a Barrage or Special attack, their gauge will be too depleted to Dodge-- this is your chance to unleash a Barrage.
Learn to see the weapon range before doing a Barrage. There are weapon icons (can't remember, probably near your ship icon) that are red when out of range. Make sure every weapon is within range before you Barrage, to fully maximize your attack. Of course, you can also opt to just do a Barrage of your main laser gun, to whittle down a tough opponent's health without exposing yourself to all of their weapons (also effective way to kite).