A routine is good, doing exactly the same stuff every night signals the body.
I used to put myself to bed just like Mom did. It worked. I had my bath, got in my jammies, watched one more half-hour of tv, then got into bed with one light on and any books I want. I can read all night if I want, and I never have to turn the light off - just like when I was a kid. And after a while, the same thing started to kick in - I fell asleep within a half-hour.
Another thing I tried once, just to overcome the night owl thing, was forcing myself to watch Star Trek on Sunday at 10am. Then I'd be up for the day.