There is a group of monks who originally worshipped the god, Gorn. Gorn's prescripts prohibited the drawing of blood of thy fellow creatures, it did not prohibit the use of body to bring people into the light which is the Almighty Blessed Gorn. These monks developed a series of skills based upon a bare-handed fighting style. Through speed and skill these fierce and faithful followers fight with purity of body and soul for the glory of Gorn. Since that time, there have been factions which have split off and started worshipping their own gods. They have, however, maintained the practices that have existed for the past 2000 years.
Monks in General
Monks are naturally suited to tank with high dexterity and many counterattack skills which increase their effectiveness as tanks. They also get a decent amount of mana which can be useful in a pinch.
While monks (and shadowfists) are better tanks than hitters they can do hitting with the right gear, particularly with a gorn worship. Hit roll (hr) is important as well as damage roll (dr) on gear since you want as many of the monks multiple open hand attacks to hit as possible.
Good creatable races for monks are orc (good hp, dex), ogr (much better hp, lower dex), kzn (much better dex, lower hp), gar (armorstone, orc-ish hp, golem option). Good remort races are trl (revival makes trl monk a super tank), drg (if you can handle the tnl), grf, gol, min. Despite the appearance of being a dex-based class, dex has little impact on a monk's ability to crane style and therefore counterattack, so for the time being, brute races are preferred, and delicately-built dex-heavy races are generally avoided.
Imps are also a great choice for monk, but as usual they are terrible until later evolutions. Also, they cannot worship until lord, but this isn't a big deal for a monk anyway.
Monks at Lowmort Tier
Depending on race and the way you level your monk, it is easiest to use weapons instead of fighting open-handed. At level 10 you get inner balance and at level 15 you get scorpion style, either of which could be a turnpoint for your race. If it's not (you'll have to experiment and see), it's wise to wait until level 25 where you get your open hand third attack.
Recommended stat training order is: wis, con, int, dex, str. You can reverse str and dex, or maybe mix em up a bit, it doesn't matter much. The first three are best trained in the mentioned order though.
Since gorn gives such a nice practice cost decrease, I'd say wait until level 10 before you practice, or maybe practice dodge (and maybe fast healing). Unless you decide to open hand early on, then that is a must (but not recommended). It's best to practice open hand as soon as you stop using weapons.
Monks "normally" worship Gorn for his bonus to open hand damage and other monk related activities. Werredan is also popular, for the hp bonus and the xp bonus. Your open hand dmg will be somewhat nerfed, you'll rarely counter, but damn, you get a big hp boost. Quixoltan gives good stats and also helps a bit with monk damage, but increases lag on skills and spells.
Monk Prestige Options
Those Monks who have more sinister desires may opt to become Shadowfists at any time from Mortal level 50 to Hero level 100.
Monks at Hero Tier
Monks usually serve as tanks at all tiers.
Soloing: Soloing is possible, especially with a gorn worship. When soloing spelled, go for as much AC gear as you need... that's general advice, but it is mostly dependent on how much hp you have. Note that some hit gear has armor (-ac) bonuses, and conversely some AC gear has hr/dr bonuses. Unspelled soloing is a lot harder, but not impossible. You'll need a mix of ac and hit roll gear for that (without losing too much ac), and lots of patience.
Tanking: Monks are great tanks. Remember to keep your hands free (no shields, no swords) for using your monk abilities. Your ac is going to be less than you're use to, but you should be fine with around -650 (-1200 with spells). Monks are a versatile tank, they have good enough hp, plenty of mana, and inclass rescue and trip. Like always, try to trip if you are just fighting one mob so you don't get the rescue penalty to ac. If you don't have a basher in the group and you want to keep a mob in place, try Tiger Stance; it lands a hit after every toss or trip, so you'll always be the first person to hit the mob while on the ground, keeping your groupies safe. Bear Stance is also very useful; it removes the hit to ac you get from rescuing. Since monks can still do some damage in tank gear it's worth trying to get pieces that also have some +hr/dr. Pieces such as: Mega's Spark, Orkenfyr signet ring, Smoldering Crown of Dying Fire, Aura of Elemental Strength, all have the same armor class bonus as the best piece for that slot in a tank set but also offer some +hr/dr.
Hitting: Right now, people are of the opinion that monks shouldn't be hitting. Their hitting depends on hit roll as well as damage roll, so check the hit gear list and favor items with +hr as well as +dr. Emu Stance will probably be a monk's best friend while hitting, as it raises maximum kick damage by about one damage verb, however it doesn't increase minimum damage so you will still occasionally miss or hit poorly.
Monks at Lord Tier
Monks are very useful at lord. Their counterpush skill is very useful since lord fights are much longer than hero and a bashed mob gets hit significantly more. They also do an appreciable amount of damage (nothing close to a caster though) with counterkick and emu stance. Also, with good tank gear, monks rarely get hit by normal lord mobs.
Monk Remort Options
Monks can remort to paladin at lord 100 (200 to keep race) and priest at lord 150 (300 to keep race).