I'd really hate to argue with Dentin on anything, but I definitely have to disagree on a lot of points. Your main concerns in making a tank character are your stats, early on, when practices are easy to come by and plentiful. Con is the most important as it directly affects your hit point totals when levelling. When you're the one taking the beating all the time, you want a lot of hit points. Dex is very important, as Dentin said, for dodge and parry. BUT so is Str. You may notice when fighting weak mobs that they are sometimes "too weak to parry your blows." Str is also requisite for most warrior weapons of any value, whether hitting or tanking, as well as shields. And don't be afraid to MAX THE STATS EARLY! Run them right up to 25, because it gets a lot more time consuming and difficult to do it later on. And it's always nice to reap the benefits of maxxed stats early on, as well. As a side note, for those times when you're hitting, of which you will have plenty, Str also directly affects your total movement, the same as Con affects your hit point total. And all of the aggressive combat skills use movement.
As far as EQ is concerned, look for things with good ac values, and no other effects, and make sure they're Type: ARMOR when you identify them, as these items are enchantable by higher level clerics. There are multitudes of other players who can enchant EQ for you, and most are readily willing to do so (chances for easy exp and the possibility of bragging rights are what make the clerics what we are

). Other things to look for in tank EQ, other than the base ac value, are Effects by hit points, Con, -armor, Dex, Str, hp regen, parry, and the rarest of all, dodge. Parry and dodge effects on EQ directly effect your skill value when fighting, and can be IMMENSELY useful. After all, if they can't touch you, they can't kill you. A lot of the staple enchantable EQ in the game is lower- to mid-level, and surprisingly easy to run, so keep your eyes open while you explore new areas as you progress through the game.
Fehlan