It's a simple matter of burning fuel to push reaction mass out the back end of the rocket. With Newton's Third Law, you get forward motion. Use mini rockets for maneuvering, and there you have it. Rockets in space aren't hard.
As for guns...
Lasers just don't work like that, period. Neither does plasma. I don't have enough expertise to comment on the rest, but I suspect they also don't work like that, at all.
Oh, and tachyons don't even exist. They are a hypothesis which cannot be tested, and only exist in mathematical models.
