Cognitive Behaviour Therapy - a short course of between 6 to 14 hours (one hour per week). Find a reputable therapist (in England you'd look for BACP).
Or meditation and mindfulness would probably help.
You may find sleep hygiene helps, but if you're not having trouble the rest of the time it might not.
For rare events, not trying to cure insomnia, consider zopiclone (or any of the Z drugs). You'd take one before the event; you'd get a good night sleep; you avoid the addiction problems that are risked if you take it every night.
(Obviously I'm not a doctor and this isn't medical advice).
I have had exactly the same issue, and have used a meditative technique that I learned in Nepal to help with sleeping:
Count from 27 to 1 with each inhalation. If you miss a number, ie between 15 and 14 you lost your focus and thought about something else, and missed the count, start over.
My experience is that generally I will fall asleep before I get to 1, and on extreme cases it will take going from 27 to 1 more than once, but it always ends with sleep.
The only difficulty I have now is being disciplined enough to not think "I got this" and try to sleep without the technique. Often what happens when I think that is I toss and turn for 3 hours before I just give in to the technique and finally fall asleep.
Or meditation and mindfulness would probably help.
You may find sleep hygiene helps, but if you're not having trouble the rest of the time it might not.
http://www.nhs.uk/Conditions/Insomnia/Pages/Treatment.aspx
For rare events, not trying to cure insomnia, consider zopiclone (or any of the Z drugs). You'd take one before the event; you'd get a good night sleep; you avoid the addiction problems that are risked if you take it every night.
(Obviously I'm not a doctor and this isn't medical advice).