A neat trick I heard from an aerobatics pilot was the following. To maintain zero g, he would just put his pencil in the air and chase that as if it were his artificial horizon.
Followed no doubt by a very short period of intense g after he falls out of the sky with a pencil lodged in the control lines!
(I know it could depend on the aircraft but I just remember it being imprinted on my brain that nothing is loose when doing aeros!).