I'm fighting against insomnia. It had beggining for a year ago.
To be honest, the only one thing helping me are meds. But please don't try to put in anything without doctor's permission!
Also such advices can help:
1. Reading bookds before sleeping. This is individual but usually books calm down.
2. Put all gadgets away. Idk there were some kinds of researches about the connection between them and  the quality of sleep
3. Don't take a nap in a daytime! Really it begins very hard to fall asleep in the evening then
4. Some warm bath or shower