The majority of my clients are in their twenties and are coasting along on their pretty much problem-free skin, not stressing too much about skincare routines or facials. And none of them ever are using eye creams; most women wait until they see their first line and freak out and purchase every anti-wrinkle product they can find.
But I do see a very large percentage of young brides with pretty signifigant darkness under the eyes, and this is often caused by dehydration. To avoid having to use too much concealer under the eye to cover this, I always urge them to buy a good basic eye cream. Kiehls makes some great mid-priced ones, I also love Clinique All About Eyes and Philosophy Hope In a Tube.If dark circles are really pronounced(either hereditary, you smoke, you don't get enough sleep, or you suffer from allergies) look for vitamin K in the eye moisturizer you choose. Also be sure to drink enough water; that should help your circles well.
Try to get on some type of skincare regimen a few months before the wedding. I had a bride a couple weeks ago who was investing in regular facials and her skin was so radiant and glowy, she hardly even needed foundation at all. (And how nice would it be to totally forgo makeup on the honeymoon?) If you are on a budget, check out a beauty school near you-you wouldn't believe how inexpensively you can get facial treatments. A series of eight glycolic peels(very good for acne, sun damage, acne scarring, and just improved clarity) or microdermabrasion is about $180 at the school I attend, and most spas charge about $100 per service.