I want to sleep over at my girlfriend's house, but I'm too used to just sleeping by myself versus the nude hotness lying there.  How do I get used to adjusting?  Are there any tricks that I could use?  

... I thought this was you having problems sleeping in your own bed, in which case I would have adviced Alcohol etc, but with someone lying next to you? brrr... good luck though mate!

well thinking this is a serious Q and not you just bragging a bit about moving in with your gf :P I would say the answer is rather simple

some 'exercise' (if you know what I mean) on the bed would help you sleep like a log afterwards

Sharing a bed keeps me from getting any sleep whatsoever. I've attempted this twice now, and twice have pulled an all nighter. And sex will definitely relax my ass, but won't put me to sleep or even help there

wait... you got a girl in the bed without drugging her?

Not sure if this is the route you choose to go, but masturbation releases certain hormones that make you tired. That's the trick I used to use when attempting to fall asleep somewhere in a strange place.

You shouldn't be doing much sleeping...

LOl it should be easier!

Firstly, there should not be any sleeping.

Secondly, have an early morning, read before sleep time (after sex)... or take a pill or two if this is only on occasion.

Just drink a lot of alcohol, it'll help you pass out easy. I've been using the booze sleeping method everyday for over a year with success every time.