I haven't suffered from serious bouts of insomnia since university when life was a stressful wreck.
All I did was not force it. If I lied down for 15 minutes and felt like I wasn't going to drift to sleep I'd simply get up and work on school stuff. Typically reading boring and uninteresting textbooks for a couple hours would leave me ready to sleep again. At which point I'd lay down, turn on the tv for some background noise. Set the tv sleep timer for 30 minutes, put a shirt over the tv to dim it's brightness and try again.
Rinse and repeat until success.
All I did was not force it. If I lied down for 15 minutes and felt like I wasn't going to drift to sleep I'd simply get up and work on school stuff. Typically reading boring and uninteresting textbooks for a couple hours would leave me ready to sleep again. At which point I'd lay down, turn on the tv for some background noise. Set the tv sleep timer for 30 minutes, put a shirt over the tv to dim it's brightness and try again.
Rinse and repeat until success.