Hey just started playing skyrim again on my main character, finished the main storyline and dawnguard I only have Dragonborn left. I'm trying to level up abit before handling the questline but I seem stuck at 40, the progress bar has barely moved at all despite completing side quests and killing alot of enemies. Any suggestions?

You level up by leveling your skills. Quests have no effect. Level whatever skills you use.

Of course, once you're in the forties, leveling goes real slow.

And it'll only get slower at level 50.

Are you sure you want to keep leveling? Once you're around that area things stop leveling anyways.

well mainly trying to complete the blacksmithing tree ( which is maxed out) but I want to be able to make everything, so I need to level up for the last 2 perks I need, my primary skills, smithing, enchanting, two handed are already maxed.

If you have patch 1.9, you could make Two Handed legendary. It actually isn't all that bad. You'd be surprised how fast it will level again.