Lavender EO for me. Try sprinkling a few drops on the sheet under your pillow, so the scent isn't overwhelming.
Also, this is very counter-intuitive - but try a cool shower or bath. THe body temp drops in preparation for sleep, so if you take a hot shower or bath, then your body has that much more heat to shed. The cool shower (I usually shoot for slightly below luke warm) will perk me up right after the fact, but in a few minutes I'm ready to conk out.