The more solid you make your frame so the trailer doesn't bounce on your tires/axles, the more solid your trailer will be.
Try a Valterra Stabilizer
and also try something under your steps
. Or, simple scissor jacks at the axles will also help. The x-chocks help the front to back motion, but you need something to shore up the total frame.
Just remember, the OEM "stabilizing" jacks mounted on your trailer only stabilize to a point. Many of us have taken other steps to firm up our trailers even more.