actually, there's a book by Helen Fisher called Why We Love: The Nature and Chemistry of Romantic Love. She did research on the neurochemistry of romantic love and she suggested a list of possible factors to why people fall in love. One of them is "Proximity". In short, pag palagi mag-kasama, nagkaka-developan. Another one I remember is the "Excitation Transfer". Ang example niyan is kung magkasama kayo na na-experience ang isang event where you're adrenaline is pumped, yung feeling of excitement is transfered into a feeling of affection/love. So, kapag daw mag-dadate kayo, make it exciting. Ride a ferris wheel, roller coaster, watch a very scary movie.. etc. Ganun. I don't know if it works but her theories are spot on.