Here's a technique I've enjoyed. I find it's most effective when I'm lying down comfortably, e.g. in bed or on the couch, with my eyes closed. It's particularly helpful if you have a headache or other tension in the head.
Take a few steadying breaths.
Now:
feel head pulsing
...
feel heart pulsing
...
feel pulses dancing
...
feel dancing spreading
...
feel dancing warming
...
feel dancing softening
...
feel dancing dissolving
...
feel dancing flowing
...
feel flowing dancing
...
feel head pulsing
[repeat method for as long as you want]