It may require some practice. Imagine that your body is inside another immobile body and that you are able to phase your body through the immobile body. As far as what movement to make when phasing the body through the immobile body, I find that rolling out is convenient because it doesn't require additional acts of dream control like floating or sinking.

Alternatively, hypnagogia and weird bodily sensations can be used as a signs to do a reality check. A motionless reality check would be best, but doing a nose-plug would not hurt much. If the reality check indicates we're dreaming, we can simply get up from bed to enter the dream.