Best thing you can do is exercise so that you burn off energy so that you're tired, and as a useful side effect you can get fit too. Tied in with that if you get into a regular sleeping pattern then you should sort yourself out. Go to bed at the same time every night, something like 9 or 10pm, regardless of if you're tired or not, and then get up at the same time every morning 8 or 9am, again regardless of if you're still sleepy or tired. It may take a few days to get into the rhythm of it, but that should sort it out.
Insomnia can be a right pain, but if you're constantly changing your sleeping habits then you're not making it any easier for your body to know if it's supposed to be waking up for the day, in full swing, or winding down for rest.
If you're looking for something to help get to sleep then honey is a good, so you can try and have a honey sandwich or honey on toast before bed. There's also hot honey and lemon as a drink which is quick and easy to make too. Boil some water, while that's doing then get a cup or a mug or something, add a spoonful of honey, or to taste, and then add a glug of lemon juice over the top. Add the boiling water, stir until the honey dissolves, drink and enjoy.