I had issues with sleeping when others do for a long while. I do not anymore (although get out of sync again about 2x a year).
1. Caffeine and you: You have a certain sensitivity to this drug. You may also be misusing it. Generally speaking, it's a late morning, early afternoon only drug. Late morning is the only place it starts working as its an adenosine antagonist, and you don't start getting adenosine in any really effective amount in your brain until then. (Adenosine is the neurotransmitter which makes you sleepy because you've been up for a certain period of time).
If you drink coffee (or soda) when you wake up stop. Cup #1 of coffee is the Earliest you should use it, and shouldn't happen before about 13 hours before you want your "bed time" to be or about 3 hours after you get your butt out of bed (so let's say "11 am". All it does before then is a brief heart rate spike from the adrenaline surge, or possibly help with caffeine withdrawal from yesterday (which you will not have issues with if you use your caffeine only between say 11a-4p)
The bloodstream half-life of caffeine is 4.9 hours That means it takes about ~10 hours to 1/4 the amount of caffeine in your system as when you stopped drinking it. Additionally, as its an adenosine antagonist, its effectiveness skyrockets the later in the day you have it in you. So if you're shooting for a 12pm bedtime, stop drinking by 2pm-5pm to significantly reduce your blood stream level by bed time.
2. Your bed and you: What are you allowed to do in your bedroom from now on? Have sex, sleep, get dressed. That's it. If there is a tv in your bedroom, say bye bye. If you read in there, say bye bye. If you touch your bed during the day, stop it. If you're sitting there with thoughts for tomorrow, stop that. If you can't stop that, you have to schedule a time of day considerably earlier than bedtime where you lay out tomorrows tasks.
If you're laying in bed for more than 30 minutes without sleep, up and at em, go read in a different room.
3. Routine: You need to get into a set pattern. Set yourself a bedtime. Start winding down before that, not playing video games or watching TV, (especially sports or TV with lots of faces) in that hour before bed. Setup a ritual for sleep, including oral hygene, preparing for tomorrow, etc.
4. Reduce alcohol consumption: Alcohol lightens the depth of sleep. Especially while getting used to a schedule, restrict your intake.
5. Cool down your house at night. I don't care if you like the thermostat in the high 70's most of the time, at night you want high 60's and hide under warm blankets. It really really really will knock you out.
6. Lights are something people are sensitive to in varying degrees. I suggest erroring on the side of expecting yourself to be light sensitive. Use tools like f.lux to drop monitor brightness after sundown. Use timers to turn on/off lamps to make your house have a sundown. Eschew bright, overhead lights before bedtime. If your TV has multiple video settings, even make a TV setting that's overly dark to use past a certain hour.
On the flipside, try to get a North eastern room with lots of windows. Try to live as far south geographically as you can. Make lights turn on like crazy (again, timers) before you want to be waking up. Create lots of noise in your living space (not alarms, but things like tvs, etc) around the time to get up.
7. Eat breakfast, and to really reset yourself, eat nothing 16 hours before you want to wake up. (This works VERY well to fix jetlag).