Druids wear light armor as Danidas said.
Armor will be very important for you to raise both attribute and non-attribute stats. Since druids are among the "Squishy" in the game, AC or other "protective" armor isn't nearly as important as gear that will enhance your dps, energy, etc. (If a quest armor reward is other than light, you won't be able to use it, btw.)
One thing I didn't know about for quite awhile as I was leveling up was spell damage focus (sdf). You'll want to have sdf at about 10x your level, i.e., level 20 should aim for about 200 sdf.
Others may have better ideas but my suggestion is to look for int gear first, wis gear and sdf next, and then look for spell damage rating, crit damage, vit/con (depending on what you have chosen for that attribute slot), etc.
You can interchange weapons and focus items to get as much of a stat boost as you can. Druids don't melee (except for entertainment purposes), so keep your eye open for weapon slot items that will particularly boost int, wis and sdf.
Hope this helps