Keep in mind that everyone is different, and there may come a point where you have to accept things as "good enough", but from my time seeing a sleep specialist, these are the best ways to improve your sleep quality:
1. Get up at the same time every day. Try not to push it more than an hour later on the weekends, or two hours on vacation.
2. The old adage about getting 8 hours of sleep isn't right. Many people don't actually need that much.
3. Don't go to bed until you're falling asleep (do your nighttime routine of brushing your teeth and such before this).
4. If you can't fall asleep after 15 minutes, get out of bed and do something until you feel like you're ready to fall asleep.
5. Your bed is for sleeping (and maybe sex). Nothing else.
6. Your room should be as dark as possible.
Regarding #2, a compressed sleep schedule may help you. That is, if you're going to get up at 6am every day, try to aim for an 11pm bedtime. If you still have trouble, try 11:30, and then midnight. In some cases, it's necessary to go for extreme sleep compression - as little as 4 hours a night, but this is usually done as an in-patient program, and generally shows results within a couple of weeks.
Caffeine, alcohol, and sugar can have a major effect on people, although everyone processes these at different rates. Cutting back or stopping consumption earlier in the day can make a big difference.
Consistency is key, and if you're doing a lot of traveling, it's going to be much harder.