Bugman, the first thing is this:
Do not associate waking activities with your bed. Apparently, this queues your mind to think that bed = activity, such as reading, for example, instead of rest and REM sleep.
Second, many people find that white noise can help, like the droning of a fan, which is why many I know have difficulty getting to sleep when it starts to get cooler, and they no longer need the fan in the window.
Third, physical exhaustion can help, but you need to plan ahead with that.
As Mage jokingly suggested, masturbation does clear the mind and relax the body, allowing you to ease into sleep.
There are others, but they have left my mind for the moment - I do hope that helps.
Oh, yes - I find sometimes that what helps me is the density and form of the blankets - sometimes, even if I'm perfectly comfortable, the blankets allow too much movement - if they're a bit heavier, as in one more layer, it "calms" my body and allows me to "settle" in.