Try doing your ghost strum with your palm heal muting on or close to the bridge. Also mute all the string with left hand so you are not worrying about the chord clarity. Kept your wrist relaxed. You can start with a just muted strum, then work in clean strum. One measure mute another measure clean, the work into what ever strum pattern your working on.
Strum patterns you don't even need a guitar to practice.. Belly guitar as my wife just name it.
hope this helps