My almost 7 month old has been rolling from back to belly since she was 4 months old and only towards her right side, but hasn’t mastered rolling from belly to back or towards her left side. She gets frustrated when she rolls to her belly and I try to leave her to figure it out but she ends up properly crying after a few minutes and I end up rolling her back 
We’ve tried lots of floor play time and tummy time but she doesn’t even attempt it, just lies on her belly with arms and legs out like a little parachuter! What else can I do to help her?
As for other skills, she can sit up unsupported and could sit for ages before eventually toppling over, even reaching out to pick up toys then straightening up again. Hand/eye coordination very good and can feed herself, replace own dummy, passes toys from one hand to another etc it’s just the rolling she seems paused on! I worry that she’ll roll onto her belly at night and not be able to roll back.