Gloves are often the last piece of gear thought about, but your hands are pretty darn important. If you bang them up too badly, someone else may have to help you do the simplest of things (including wiping your own ass). Get some good gloves so you can still do all you need to, even if you wipe out.
1. How Do They Fit?
Get gloves that fit. The best damned gloves in the world won't be as comfortable nor provide the right amount of protection if they don't fin you. You need them to fit snugly, but not so tight that they pinch your hands. They should be comfortable and breathable.
2. How Do They Feel?
While the gloves need to fit, they also need to feel good. Super stiff gloves may break in over time, but you can usually tell right away if the gloves feel right. A lot of it depends on how they fit, but even if the glove fits right, make sure it feels right. Remember, you do a lot with your hands while riding and you want to be sure you can feel what you need to feel even when wearing a pair of gloves, If you feel totally cut off from the bike by wearing gloves, you probably have the wrong pair.
3. Whats the Quality?
You can usually tell a good pair of gloves the moment you put them on. They'll feel sturdy yet comfortable. Look at the material they're made out of, check the tag if possible to get specifics. Also look at the stitching. No sense in paying for great leather gloves if they have crappy stitching. You can usually judge quality by trying gloves on, but if you're buying online, stick to well known brands and you'll probably be fine.