For women, it's all about sun protection, Vitamin C, retinols, exfoliation, moisture and not clogging the pores. Exfoliation can be accomplished a dozen different ways: clay masques, glycolic acid pads, gentle scrubs, enzyme peels, sonic brushes. The thing is not to overdo it. You don't have to spend a huge amount of money--ignore branding, learn how to read labels--the first five ingredients are 90 percent of the product.
Constancy is the most important thing. A good diet is central to health, not just skin.
For men, it's a little different. Testosterone is going to dispose you to acne and oiliness for a much longer period of time but it will keep your skin younger. Also you exfoliate daily by shaving. i would concentrate on daily sun protection and some nightly repair with vitamin C, retinols and other proven ingredients. Salicylic acid products are great for oily skin because they help de-gunk pores.
If we're talking about additional serum ingredients, I suggest hyaluronic acid, ceramides, copper peptides (but not in conjunction with Vitamin C), niacinamide, COQ10, phopholipids. Read Paula's Choice for more suggestions and good critical reviews.
Not a fan of pure aloe (unless you have a burn), baking soda scrubs (wrecks you pH), sugar scrubs (particles are too sharp), Queen Helene's mask if you are fair-skinned (it will break blood vessels). Have never tried pure coconut oil other than on my hair.
I do think the tissue-derived products such as TNS are amazing but am not motivated to pay their prices. If you can, go for it. Also don't expect miracles. It's better to look your own age than peeled, plumped and pulled to oblivion.
Finally, ignore bullshit hype brands like La Mer that are based on image and appealing to a particular clientele. Korean and Japanese brands have some great bargains.
