ooh, i'm a highlight addict! I tried to stop for about 4 months and then I just couldn't resist! Now i'm taking a short break for a while again.
Um how about a few only in the front to frame your face to see how you look with them. You don't want to get chunky or thick stripes of them at first either. I dont recommend any person go too light at first. No matter how light you are, it doesn't mean you'll look right. What tones do you have in your skin? I have mainly yellow but I have sensitive skin so with the slightest rub or form of irritation I turn red. Can you post a few pics of you or describe yourself somewhat. Also what is the haircolor you have now? I'll be able to help you further with that information.
I would say to start with you want to go only a couple shade lighter than your original color at first. And do so very slightly....and as you get use to it, you can do more. Some people....like me, like more than one color of highlights and it tends to break it up a bit and not look so drastic....I love my highlights. I'm addicted I think to hightlights. LOL!