I'd disagree with Stormtrooper. If you take something to fall asleep, you end up relying on that thing rather than getting used to the diapers. I think the only way to do it is to just find a good 3-4 day period where you can consistently get to bed on time and even with a little extra time to get some sleep if you're struggling with it. You'll have a couple of rough nights and then get used to it.
Alternately, you can wear to bed for a little while, try to fall asleep, and if more than ~20 minutes passes, just take the diaper off and try again the next night. It takes longer that way, but if you do that for a couple weeks, you'll wind up getting used to it.
Also, if you are too hot or actually uncomfortable (rather than just being conscious of the diaper) then definitely shift things. Move blankets around, try different pajamas, or shift your position.