If you come to think of it, it is love after all and not magic. Therefore a gradual way to the heart is all you need. Make steady eye contacts, to show that you are really into what they are saying. Show some interest in their personality and back story. Find similarities and complements. Try to give them some attention and do not always be the attention seeker. Make them feel acknowledged and appreciated in this world. Smiles and nudges work a lot in this favour. The most important thing is confessions, about what and how you feel about them.