For instance my face is naturally round so I would want to have brows with a high arch. I try and avoid those rounded eyebrows, you know the ones that are shaped like a rainbow. That look isn't cute on me. The goal is to find out your face shape and find which brow is best for you. My tip would be to go to a professional and have them help you decide.
If you haven't had your brows professionally done a great place to go is ULTA at the benefit brow bar. It takes about 20 minutes to get your brows done and they draw all over your brows, color them in, and show you what the finished product will look like before they start the waxing process. I love how they use a gentle wax and don't double dip. They also give you a free brow wax on your birthday so take advantage and see how you like it!
When you get your brows done speak up and ask questions. Those girls or guys are professionals and will walk you through the steps of achieving your perfect brow at home. If you're still hesitant about going to a professional and you like to do things at home check out benefit cosmetics for eyebrow tips and tricks.