Re: Gucci look - any tips ?
You have to be able to understand to some degree what what most likely existed in the original shot to maintain perspective here. Her cheek probably didn't look like that, but I don't care for that detail. This looks like it was scanned, so gradation was probably lost in that area. Much of it is lighting. Those shadows and several of the highlights suggest a fairly high sun. You might be able to get that in a studio too, but it would take a lot of control. Any bounce from backgrounds or walls would have be carefully flagged so as not to mess up the shadows. There are parts that are obviously darkened down in areas. Her arm wouldn't light that way, and the highlight wouldn't be that continuous. It starts from the lateral portion of her deltoid and tracks close to part of the tricep. It's possible to accentuate stuff like that in post, but you have to be careful not to make it look too even along the border. You can find a lot of that online, and it looks weird.
You would probably have to trace those shadows to get both the hue and density just right. Some of it could be done overall, but they are sharp and don't cause issues along their borders. That can be annoying to achieve. The sunglasses are way retouched as are the lip highlights. Lips are clearly balanced for color. I think the forehead highlights are mostly natural, but the noses are somewhat painted.
I would definitely point out that if you're having trouble figuring out what was done, you will have a lot more trouble doing it yourself. It is far more difficult to execute something from a set of images to something final and approved than to break down what went into it. After all if all you have to look at is a set of images from a shoot, you aren't working to a completely known target. No one has seen the final image at that point. I hope this helps.