How do you make someone fall in love with you on elders scrolls skyrim

Speak to the priest in the Temple of Mara in Riften. He will explain that courtship in Skyrim is short, and that people wear an Amulet of Mara to show they are available and looking for a relationship. He will sell you one (note that you may have found one already, but the marraige options only become available when you speak to this priest). Wearing the amulet and talking to people will show that some are interested, possibly many people you already know, such as many of the Companions. Some characters require you to do something first, and this can differ depending on characters. Some require you to do a mission, some want a gift, etc.