Your body tells you what it needs so listen to it.  When you need to nap, take one.  When you can’t sleep after 30 minutes, get out of bed & do something quite.  Even just to walk around, then try again.  Make your sleeping environment cool, calm & soothing.  Try to set a sleep schedule that is consistent every day.  Turn the lights out & shut the TV off.  Avoid caffeine, alcohol & large meals near bedtime.

These are the things that work for me.   We are all different so you must find what works for you.  I also take 6 mg of melatonin before bed.  It helps me stay asleep.  The biggest factor seems to be: Shut your brain off!