For bouts of insomnia a low dose of melatonin, the hormone normally produced by your body when it's time for sleep can be helpful, but don't use it permanently, lest your body stop producing its own stores. I especially rely on this one when I have terrible jet-lag.
More info in French.
2. Essential Oils**
My favorite mixture is:
6 drops Lavender essential oil (I use officinalis)
1 drop Sauge Sclarée (Clary Sage)
It can be used in a diffuser, or, if you'd like to save yourself the expense, mix it and put a drop on your pillowcase (may leave a stain) or on a tissue between your pillowcase and pillow.
It is also relatively easy to find lavender eye pillows. The added gentle pressure on the eyes feels pretty good, but it doesn't have the sage. Parisians can find nice ones at Yoga Concept.
3. Reduce Screen Time at Night
There are new scientific studies that show that using a screen right before bed/in bed can seriously mess with your ability to fall asleep and to have deep sleep, so I now plug my phone, take a hot bath/shower, then go straight to bed. That way, there's at least a small window between when I last look at a bright screen and I go to sleep. If you must check your phone/computer in the evening, try to have the brightness set on the lowest setting for your phone and there's a free computer app called flux that adjusts the screen brightness for you with the changing ambient light.
I sometimes find that I don't sleep well if I haven't had any exercise. So try to get some exercise in every day! Yoga, a brisk walk, etc. Here's a study that supports that.
5. Mindful Relaxation
If none of the above seems to have worked, try 'savasana' or a guided mindful meditation. It also works well to get back to sleep if you wake in the middle of the night.
I hope you get some good restful sleep!
*Please consult your doctor before taking any medications.
**Use essential oils sparingly and cautiously.