You got to do draw out. Draw lines, circles, swirls. Draw till you can get it good. Then try small circles and big circles in a paper. Then you try on your hand. Its actually easy if you know the basics.
Can you please, put a learning video on how to put the mehandi design thin and thick and also how to hold the mehandhi and how to make a small opening in the mehandhi, bcoz it will definitely useful for many people, I hope u will definitely accept my request .