What you have to do when you fall in love to someone?

You can't do anything. If you don't want to fall in love with them then distance yourself from them. But you need to think if i didn't like them then why am i falling in love with them? If you wish to fall in love with them then let yourself, but nothing lasts forever and there's a difference between 'lust' and 'love'. I f you love them, GO FOR IT!!