I wear form-fitting lycra pants. If the fabric layer is tight against the skin, it reduces the friction on the skin itself (it's transferred to the fabric instead). You can wear them under looser clothing if you're trying for a certain look, but most athletic stores carry a wide variety of this type of clothing. Some types even have lifting and firming capabilities and make your butt and stomach look great when wearing them.
Try them on and make sure there are no wrinkles or hanging loose anywhere, but you don't want them so tight they feel like they're cutting off circulation.
Also, be aware that if you're exercising enough to get sweaty, lighter colors will show that. So stick to black or crazy color patterns, or it will look like you had an accident when you get in a good workout. ;)
Powder works for a short time if you're not expecting it to last all day, but if you're a woman, you should be careful about using talcum/baby powder in the groin region as there have been recent reports that it can increase cancer risks. Most places sell powder cornstarch as "bath powder" now and there are things like Gold Bond Medicated Powder(or the store brand knockoff that is likely the namebrand for much less the cost).