There are also some vids (youtube search or google search) out there on how to go from a trapeze to a double or nothing. If going straight to double or nothing is giving you problems, you may want to try the trapeze to double to see if you have more success with that approach.
Also, if you’re in an area near where a yoyo club gets together (check the Yo-Yo contests, Clubs, and Events section of the forum: http://yoyoexpert.com/forums/index.php/board,4.0.html ), try and get to one of the meetings/jam sessions, so that maybe some more advanced players can watch how you’re trying and give you some pointers.