Dr. Kinjo is close.
Sip warm milk, or try a hot bath, don't use POT TO HELP YOU SLEEP! Thats just abusing "medical marijuana".
Breath in through your mouth and out through your nose, its a calming tactic used in several situations, anxiety attacks, asthma attacks, panic attacks, ect. and also helps with sleep.
Cold temperatures put some people into a hibernation-like state, so the fan idea is alright. Also try natural sounds, but I would suggest against water-things, because they could result in.. accidents.
Don't eat a lot, while you are asleep your body digests differently, and will make more fat, which most people don't want. It will also wake you in the middle of the night because you will have to use the rest room.
Exercise releases endorphins and will really wake you up, even if it exhausts you, it does release happy hormones that cause wakefulness.
Another way a lot of people have been able to lull themselves to sleep consist of imagination exercises.
One common one is imagining a peaceful land with a calm river. Then slowly as thoughts that keep you awake come to mind, throw them in that river and let it carry them away, and let your mind be at ease.
Another common one is more like sleep yoga. Lay comfortably on the bed with your eyes closed, this method commonly has soothing music in the background. Let your limbs, starting with your legs feel like rivers, calm and flowing, then let your arms do the same. Tell yourself you are tired, and clear all thoughts from your head. Imagining your limbs taking on the consistency of water, causes tense muscles to loosen, and convincing yourself you are tried is similar to the placebo effect.
Other suggestions are just to lie, with all lights off, and wait for sleep to come. The mind is set to naturally become more awake with light, because we are not nocturnal by nature and the rising of the sun causes our minds to awaken more.
=D Good luck next time!