I've only played the CrossFire mod and I think its excellent but if you cant cope with the vanilla difficulty you will be toast - it's a lot more difficult. I'm not an amazing player but I got up to standard after 3 or 4 hours.
Get rich quick by selling captured enemies and
buy a better ship and equipment as soon as possible... check the CrossFire wiki for where you'll find the stuff for sale and where the prisons are to sell your prisoners. In combat keep moving, dont fly in one direction for too long... double back and attack anyone who's pursuing you and
concentrate on attacking one target at a time - get his shields down and then blow him up. There are 3 different types of weapons and 3 corresponding shields to protect against them. If youre stuck on a set piece battle, your weapons may be the least affective against their shields and your shields least affective against their weapons... you can look up your enemies in the wiki and see what loadout they carry then change yours to suit.
nimbo77: Ages since I played, but I still remember stumbling into a place somewhere and seeing this huge rotating circular thing in space, might have been a black hole. It didn't appear to have any function other than being a background object, but it was almost like an epiphany.
I think thats a quasar thats got two huge cones of stuff shooting out of the poles. CrossFire adds loads of content like that.