I have posted on this a few times, and I think it might be a good trick...or maybe I am just lucky. I keep my mouse alive all day in the feed tank. Then I kill it right before I put jub jub in the feed tank and he always goes for it. I think the scent of food is a partial key which gets him ready.

Also, I have read to feed when they are hunting. Watch your snake for hunt like activity, i.e. putting head up for no reason and staying still while it is crawling around. Move then stop for no reason and waiting. That kind of stuff.