Always ensure that you don't let the mask rest for long. It will harden and become difficult to remove later. Always wear gloves to avoid staining your hands. Make sure you always use fresh henna powder, old powder will not render the desired result. It is preferable to grind fresh henna leaves and use it instead of buying it from the market. While applying henna, never forget to cover the entire body of your hair from root to tip. Keep petroleum jelly handy to wipe off extra paste from your forehead or from any other areas.
Make a paste by adding a teaspoon of castor or olive oil and two teaspoons of curd. oil will nourish the scalp and hair while the curd will help in conditioning. Achieve the desired consistency by adding water.
Let the mask sit for an hour and a half. In case you are pressed for time, take some steam or wrap a hot towel around your head (always wear a shower cap, you wouldn't want your towel to spoil). Rinse once done and use a mild, herbal shampoo.