Then you should definitely work on those as well. Strengthening and opening your base chakra will help keep you safely rooted while your astral body goes off. Without a safe root, it will be harder to leave. Like, have you ever tried braiding some yarn? It really really helps to tape it down to something firm first. Weird analogy, but it just popped into my head!
The naval chakra is the seat of your willpower and courage, strengthen that to help you have the will to leave. A strong base and naval chakra will help get rid of the fear associated with leaving your body.
And the crown chakra is like the doorway to higher spiritual things. One AP technique is to leave through the crown chakra, so if your crown chakra is closed or blocked, you will have a hard time wrapping your mind around the higher spiritual concepts.