The BEST method of leveling is not to do questing at all (or as little as possible). By 'falsly' raising your noriety level you make it harder on yourself later in your pirates life to obtain larger REP points from enemies.
Read this guide on Reputation and Building Stats
From your post - the guide itself may be a bit over your head - but - in later posts of that guide there are a few pointers on how to use your weapons explined easier which help out many a pirate get those hard REP points in 'older pirate age'
