Eyebrows not only frame the face, but they can also enhance the beauty of ones natural eye shape, and accentuate the look you're going for: be it an everyday or sophisticated look, the best place to start is the humble eyebrow.
"Practitioners in the field of facial aesthetics, such as make-up artists and cosmetic surgeons, have long appreciated the influence of eyebrows on attractiveness (eg Cosio and Robins 2000). During the 18th century, in fact, in Western Europe full eyebrows were considered so essential to facial beauty that some upper-class women and courtiers would affix mouse hide to their foreheads."
Ok - So, I wouldn't go as far to say if your eyebrows are looking a little lackluster that you need to go shave the nearest animal and stick it to your face... just don't ignore your eyebrows.
Ideally when shaping your eyebrows you will want them to begin parallel to the innermost corner of your eye, and end diagonally from the outer corner of your eye (see image below). When plucking or threading your eyebrows always pull the hairs out in the direction of growth and pluck from below the eyebrow. If you pluck from above the eyebrow you will end up with a permanently grumpy look. The point of arch usually appears naturally, ensure that you do not take out too many hairs if the arch becomes too high or skinny your eyebrow shape will look unnatural and a little McDonalds 'M'. If you find plucking a little too painful then either pluck them after a hot shower (the heat will open up your pores and allow the hairs to be tweezed out with ease) or rub a little ice on the eyebrow area just before tweezing to numb the pain.
If you've never shaped your eyebrows before and they're airing on the side of werewolf then it's advisable to get them shaped professionally and then you can easily maintain them by following the shape given.
The best tweezers I have ever owned are Tweezerman's slant tweezer, they cost me £17 (expensive - but a god send) or you can buy the mini version for around £12... but I find them a bit awkward to use so would recommend getting the normal sized ones. For that pretty hefty price tag you get a lifetime guarantee and free sharpening (I've never used this service but if I do will let you know)
Top Tip: If you're going for a 1950's look, after you've added the brown in for extra definition, apply a small amount of either a blue or purple eye-shadow in to the brow. I promise it won't look like you have, but it just makes the whole look pop.
I used this technique on Hannah's eyebrows: