Regulating my breathing sometimes helps. Count the breath in, count the same number while you hold that breath, count again as you slowly breath out, then try to count the same number before you re-start the cycle.
Probably at the start you may only manage to count to 3 or 4, but with practise can get to 7.
It is the concentrating the mind which often allows sleep to come.
Sometimes I try to visualise the colours attributed to the various chakra points. It doesn't matter if you believe in that or not, it is the concentrating on something specific which might allow sleep to come.
I can list the 50 states of USA alphabetically in less than one minute!!
Sadly, very often, nothing works at all.