Since you have got the Titan you have now finished the tutorial part of SP and it is a good time that you learn how to fly. Select a class 6 ship like Drake, Dragon or Barracuda, get some decent equipment for it, and then see how far you can take the ship - i.e. take missions of the highest difficulty you can find and/or tangle with local criminals where there are good, renewable supplies of them (e.g. Omega systems for Red Hessians, from Dagger over Stiletto to lvl 16 Sabres). Don't bother with the civilized worlds, though - that is Patriot/Dagger territory.
Once you have done that, you could try one of the class 7/8 ships and battle with hostile Outcasts and Corsairs in their respective homeworlds.
You could also fly the SP campaign in a Dagger, Patriot or Starflier (preferrably in that order). For other ways to have fun with the campaign, have a look at the thread
Plan for a maximum-fun campaign in the Spoiler Forum.