So I'm a lot more familiar with The Sims 4 mods and CC, but my girlfriend recently got me playing The Sims 3. While I've gotten a decent amount of mods for it (mostly NRAAS but a few others, some 18+ ...
Well, considering the game is 10 years old, it's a bit like finding a needle in the haystack if you're searching for current, high quality CC via google or something. Most of it lives on Tumblr. Here's a few helpful blogs to browse:
This one is pretty much inactive, but was active for a long, long time and has a lot of good CC to look through: https://sssvitlans.tumblr.com/
These are all active: https://pis3update.tumblr.com/
https://nemiga-s3cc-finds.tumblr.com/
https://smfinds.tumblr.com/
As for something more specific, I adore Santos Fashion: https://santosfashionsims.tumblr.com
As for getting a more HQ feel, you can use this: http://modthesims.info/d/600416/extrareal-graphics-shader.html
A custom skin, of course, isn't going to magically make clothes, hair, or anything else in the game have better texture quality. But there are plenty CC clothes, hair, and everything else that will use high res textures than EA. Also, you can use a moderate HQ Mod to make the game crisper looking. I say a moderate one, because you will guaranteed get Error 12'd using a high end HQ Mod during normal gameplay. If you'd like I can send you the HQ GraphicsRule that I use. I use it all the time, so I'll post some pics so you can get the feel for how it makes the game look.
Kurasoberina's Primer Skin in Ultra HD is a favorite of many simmers as go-to CC skin. But if you'd like, I use a skintone for my female sims that I think is awesome. It isn't available to download anymore, but if you want it I can send it to you. (It is only available for female sims, though). Here are some pics to show the skin and my HQ Mod (under a spoiler, just in case I can't stop posting pics :lol: ):