Use a logic clock with push effect for basic forward propulsion, the push engine needs to be relatively large compared to the size of the warhead/core/reactors (need a couple)/rail/logic blocks. Personally I'm strongly considering the shoot out rail version since I only tend to use them from point blank range anyway.
You can also use a bobby module + basic long range weapon system to make a guided torpedo/kamikaze bomber, however since the latest thrust changes you need to either A) set auto dampening for every single one, or B) use an alternating but slightly smaller pull effect system on a clock connected to your main push clock. Otherwise when it reaches maximum server speed the push will stop affecting it and no matter where it aims it will just keep drifting in the direction it was when it hit cap. Both of which are kind of annoying -_-
If you plan to pretty them up make sure to be really sparing on hull/not use it at all, otherwise the push/pull required skyrockets, motherboard, composite & alloy are your best bets.