I've always been able to fly in dreams without much effort, but only recently have I taught myself how to levitate properly. For me, a lot of it came from watching how Marceline levitates in Adventure Time. My subconscious just seemed to latch on to her ability and allow it to manifest in my dreams. A lot of my lucid powers are based on the abilities of fictional characters, come to think of it. Maybe this could be beneficial to you as well? Study a character who is able to levitate until the power bleeds over into your dreams. Giving an ability some context in this way makes it a lot more passive and therefore much less of a struggle to perform.