Basically try to make it clear that it is an original level. Be really creative. Don't worry if you have the standard coin warp, or even dispersement of enemies, or a boss (especially don't worry about a boss, overall you can make the level a lot more unique and challenging than jazz 2's bosses), etc. Maybe take a lesson from the first Jazz game and add multiple routes instead of a single route, that's bound to do your level good.
If you use puzzles don't go overboard or the player may get turned off to your level because there are so, so many levels with puzzles. A few are really neat, especially if the whole level's completion does not hang in their balance.
Don't worry about how many new concepts you have, that is difficult! We have been using the same game now for a while, there's onlyso far we expect you to go with your levels. But if you get a great idea, definitely go ahead with it. Try and make the whole level appear to be a really great idea.