creating randomly filled levels is easy, making them align with your gameplay is difficult.
randomly created content generally has to be suited to your gameplay, otherwise it's pointless if you can't access some area simply because the map didn't generate a way to get their.
then after having some initial map, depending on how enemy's work, it could be as simply as throwing enemy's randomly into the map, or as complicated as assesing the map for area's where enemy's are most optimal to be placed, this is the same for any collectables(coins, gold, etc).
in my opinion, randomly created content/map has to be pretty much tailored to their specific games, while their are general overviews of randomly creating maps, how that map interacts with the player is vital in ensuring that w/e is created is enjoyable/fun/unique.
it'd be easier to help you if you told us a bit more about the gameplay mechanics, instead of us tossing out random information that may, or may not help you.