I haven't generally had a problem getting to sleep. I use several of the methods already mentioned: no exciting technology (except the radio on relaxing, repetitive music - salsa is surprisingly effective! - or an even-level talk show - Radio 4/World Service or Rhod Sharp, but not Dotun Adebayo!); read a tedious book or magazine (when a sentence doesn't make sense after three attempts it's time to turn off the light); take some medication (low dose and vary the drug - Syndol, NightNurse, Sleepeaze or just paracetamol); do mental exercises (plans for the future, how to allocate a £1m winnings, etc.). I try to keep the medication-taking to the minimum because they seem to lose efficacy with continual use.
It is the staying asleep I had the problem with but I've sorted that now: feet warmer than legs, legs warmer than trunk, head in the cool. Bed-socks are effective, as is a folded blanket on the lower part of the bed. It wasn't till I tried these that I recaptured the wonderful deep sleeps of my childhood - the sort of sleep where you can get up to have a piss and fall back into bed without ever really waking up.