well.. the best way is to have your final meal earlier so that you dont feel so heavy
other ways are to drink some calming fruit teas like cammomile or hot milk , hot chocolate, ovaltine, before you head to bed.
this will calm you and help you relax and drowse off before you can start feeling all the uncomfortable aches and pains of pregnancy.
Try not to think about stressful things before you get to bed, otherwise they will be in your head all night, it gets worse during pregnancy (personal experience!)
Sleep on you left if you can as it has benefit , in later stages do not lie on your back at all its harmful to the baby as it may reduce oxygen supply from baby .... somthing like that ...
you can sleep on your right but left is said to be better, healthier.
hmm wear light clothing as it does get hot and sweaty if you got too many clothes on.
also i found that it helps to have few pillows just against my tummy , feels more comfortable.
make sure you empty out your bladder before you get to bed otherwise it will keep you up as you will be getting up several times to the loo!! some women rock back and forth to empty the bladder properly on the toilet seat , just to get the remaining liqud out.
erm i hope i have covered all i know , i hope its helpful because i am going through my 33rd week and sleeping is very difficult!!!
farewell :) x