You can make your own powder by drying henna leaves in shade. It might take weeks for them to dry to a crisp and you need to grind them thoroughly. You may also buy henna powder from the market.
1. Henna powder sieved through a muslin cloth.
2. Well strained strong tea decoction.
3. Eucalyptus oil (few drops).
4. Strained lime juice.
5. Sugar (one table spoon).
Take the henna powder in a bowl, add the tea till it becomes a thick paste (similar to a dough). Add eucalyptus oil, sugar and lime juice and mix well to make it into a smooth and thin paste.
Leave it covered over night or during the day if you prefer to apply in the night.
Make a cone....
Take a thick plastic cover or use any thick freezer bag - cut it into shape of rectange 7" X 4". Twist one corner of the cover to make a cone. Tighten the tip to make tiny hole. Hold the tip and fill the paste and tie the broader end tightly with a thread.
You also get readymade cones from the market.
Let imagination fly...
Now have fun. What ever you draw is beautiful and is a master piece in its own.
You should leave the mehendi to dry on your skin and keep it on for as long as possible (4 to 6 hours if possible - you may go to bed also with it). Scrape it after that. The color will become deeper if you leave it untouched by water for another 4 to 6 hours. A deep color may last upto two weeks. The coloration varies from person to person.