Grab the Learning Curve Quest from Proctor Quinlan from Brotherhood of Steel. Have a high powered sniper that does good damage. Once you except the quest run out to the ships dock all the way to the back there is a platform to the left. Hide behind the barrels, you need to make sure your hidden or the BoS will kill you. Aim your sniper by where the BoS guards are (not on the ship but below it) there is a scribe you kill. Once you kill the scribe run back to Quinlan and say you failed the quest and want another chance. Gives you 400 exp each time and you can level your self about 5 levels in an hour which is pretty damn good. There is a video on YouTube if my description was bad.