Eyebrows are big right now. Now I don't mean big or full as they were in the 80's, but they're important in a new way. More important now than ever. I think the biggest mistake women make is waxing/threading/plucking them too much! If your brows are too thin, it ages you. Just as when you apply too much eyeliner it ages you. It actually really makes you look youthful when you fill them in a bit. Now I'm not saying go all Frida or anything, (thanks Shaina for putting that one in my head) but I'd definitely say you need to touch them up with either a pencil, brow gel or brow mascara. Even on the days when I go light on my makeup, I always do at least concealer, blush and brow gel. It just finishes off your look and makes you look complete. If you are a beginner, I suggest going with an inexpensive brand just until you get the hang of it before switching to a more expensive option. Also, try going to Sephora or Ulta, or asking a friend who's brows you admire to help you out. It makes such a difference and will truly make you look much younger! I swear!! One last thing...always buy one shade lighter than your actual brows so it doesn't end up looking too dark after applied.
Finish off with a clear grow gel if you want extra hold