NoiVul,
cuthbert_binns, did you guys notice that when you're not firing, you're not using up your turn? Yes, the other ships move, too, and what's more important, their seekers move as well, but your turn doesn't end. Sometimes (granted, it's just luck with Krell) you can use it to actually force them together so that your torpedoes work better.
If you're in the Krell system, you should already have the Mark II engine, hopefully fully fitted with engine boosters. That gives you six shots per turn, five if you're going to end the turn manually. What I do is use all my shots but one, hide behind some asteroids (so that no enemy can fire at me after just one move), and if there's a seeker nearby, kill it with my last shot; if not, end the turn. Repeat until all enemies are dead. In most battles I don't even get hit, and it's very rare to actually lose my shields.