You've gotten a lot of different suggestions, so I just want to tell you what works for us. My son is now 19 months old, and he has NEVER been a good sleeper. Always to bed late, crazy nap schedule, etc. When we moved out here 8 months ago, I read the book The No-Cry Sleep Solution, and while I already know a lot about the benefits of a schedule/routine, this book opened my eyes!!!! Like a few others have said, within a few days of implementing a bedtime routine, he was going to bed for the night between 8:30 and 9pm. HALLELUJAH!
I've also noticed a HUGE difference in his actual sleep. He sleeps SO MUCH BETTER now that we have a set routine EVERY night with very few exceptions... even when we go to Grandma's or are not at home. Part of this difference is my own attention to the clock and not to other things that need to be done or things that I get wrapped up in.
Our bedtime routine starts at 7:15 with a bath. Then we do our baby rub with lotion, jammies on, dry & brush hair, and clean out ears. Then, it's back downstairs for yogurt (which is GREAT for natural melatonin) and hugs & kisses with Daddy. We go back upstairs (he LOVES the stairs!!!) to read 3-5 books, then we kick Daddy's out, and he nurses. It depends on how tired he is as to how quickly he falls asleep, but we rock in his DARK room (only a nightlight), and I lay him down in his crib to fall asleep on his own. It took about a week for him to anticipate what was coming next, and now if we try to skip a step, he reminds us!!! It's awesome!
I know this was long, but hopefully something in these suggestions will click with you and your family. One thing you should definitely take into account is the overall schedule of your household. If everyone gets home late from work, then an early bedtime may not work for you. As for not napping, I agree with the others about quiet time. That time is as much for you as it is for your child! Good luck :)