I have naturally thicker eyebrows and I like them. I think it just suits my face way more. Too thin eyebrows can make your face look very "hard" . It's difficult to explain what I mean by harder but I just find that bigger brows softens the face. The thing with thick eyebrows though is just that it should be kept tidy. Thick eyebrows that are untidy can look bad.
I prefer thick and GROOMED eyebrows on girls. I personally don't think thin eyebrows are attractive, especially when the natural look is in (and as you age, your eyebrow actually becomes thinner and you can't get the natural thickness back.) Overly arched eyebrows can make a girl look intimidating and angry. On top of that, eyebrows help frame your face and gives you a more youthful appearance.
As for shaping, YouTube some tutorials to help you find the appropriate arch.
Eyebrows can be a very personal thing, and many people have different preferences. As well, there are many different face shapes, so this will also be a thing to research/consider when trying to decide the best shape for you. I am an aesthetician and natural is always a crowd pleaser! Most people just tend to want a clean up of the hairs that are growing in not quite as connected to the eyebrow...
I am not a high enough rated user yet to be able to post a link.. :( but google "KANDEE JOHNSON PERFECT EYEBROWS". This is one of my favorite makeup artists and there's a few videos where she explains the process for shaping of eyebrows, and this applies to girls and guys!
Over tweezed can be bruutal! Just fill it in a bit with some shadow and an eyebrow brush (looks more natural than the pencil). Natural but nicely shaped is best. When I don't tweeze my wooly buggers they grow in what's called 'angel wings' which I personally think is the worst shape =( ... I tried to find a link but came across this instead.. nothing could be as bad as these! link
Natural with a little bit of tweeting to define its natural shape more
Thick eyebrows are the most beautiful to me. Thick eyebrows with a very soft arch make the face look more youthful. Mine are somewhere between thick and thin but leaning slightly towards thick and I wouldn't mind if they were thicker. Thin natural eyebrows aren't bad either.
The thing that bugs me is when girls go get their eyebrows done and the arch is like way severe. I see this all the time, and it makes them look old and evil to be honest. Painted/Drawn on/Highly filled in or whatever you want to call it looks horrible as well. I see those blocky stencil brows a lot too. And I don't even need to express how stupid tattooed eyebrows are.
I can understand a little maintenance but so many girls take it too far thinking it's hot and it's ruining their cute little faces.
Thin and thick eyebrows are nice, shaded too... tattooed not so much but some people have them for good reasons. It's good that they have eyebrows. :P
I like thicker and straighter eyebrows but that doesn't suit everyone. Girls still look amazing with thin arched ones! Just depends who it's on.