The power of love triangles is astonishing. It turns sister against sister, mother against daughter, friend against friend. I myself have created an eternal family feud that will persist through the generations with a Team Gale-er. And there doesn't seem to be any rhyme or reason to my choices...sometimes it's the bad boy, sometimes it's the nice guy, and sometimes it's just the underdog. But I always manage to make a choice--then change my mind about five times--then make another choice by the time the book ends and I find out what really happened.
I love to hate love triangles. I really do. Because it's so heartbreaking when she finally has to choose, and it tells you so much about her character. And I've grown to love or hate the boys along with her. Do you know why I loved "The Notebook?" (The movie, not the book.) Because they made both of those boys so compatible with her. It was her choice, it was her growth, and it was choosing the road less traveled by.
That, to me, is the best way to do a love triangle. Make both of the choices appealing in different ways. And don't, for the love of all that is sacred in romance, just kill off one of the boys. That doesn't help us (or your character) at all. It's just a cop-out. Making her choose is the most important thing you can do for her, because it lets us see what honestly matters to her. Each boy should represent a different ideal. Will she choose passion over comfort? Love over status? Desire over duty?
Now if you'll excuse me, I have to go build up some of my defenses around the fortress...the Team Stefan-ers seem to have breached security. I might need some back-up here.