Techniques
So, how do you henna your hair?
Here's the basics: part 1

I prepare my henna mix the night before.  There are lots of potential mixes.   I use body art quality henna powder and lemon juice. Mehandi.com sells Ancient SunriseŽ henna, the only body art quality henna that is independently laboratory tested for purity.  Henna from shops is often full of crud and stale, and may give disappointing results. 

Start with clean hair.  Some people start with wet hair, I start with dry hair because it runs less. 

Brush the hair out smooth because you're going to have to section it, and you don't want to pull rats!

Get plenty of old towels ... henna is messy!  If you have a nice floor, put down newspaper.  Its easier to pick up splats by gathering up newspapers than it is to wipe them up.  If you can possibly get a friend to help you, do so!