Darts are your friend:
A dart is just what it sounds like. You can buy darts at the equipment shop. Once a player reaches level 2, theyll be able to use them. Darts are basically a ranged weapon, which allows you to attack a creature from one room away. This may not sound like that much of a "trick" but keep reading.

So how does that help you? Well, there are plenty of creatures out there, that at level 2 give you great experience for attacking. At level 2 though, those creatures would soon clobber you if you were standing right next to them. So, load your inventory up with darts (or a case of darts if the version of TA you're on features it) and head to the room next to whatever it is you want to attack. Then issue the command "t dar (target)". You should end up with an attack message just as though you were attacking with your wielded weapon.

What makes this so great? Theres a few things. You get experience for attacking the creature, good experience if you picked something high enough above you in levels. Here's the thing though, the creature you're attacking... wont fight back. It cant see you, and i dont know of a single creature in TA that uses ranged attacks. It's possible, but uncommon, that the creature will move to the room that youre in, and stat attacking. This isually wont happen if you use this trick on key creature. For example, in the T1 dungeon, there are a few creatures that are placed at certain places for a reason. Like the Minotaur for example. He usually wont move unless he's chasing someone, or fleeing for his life. This makes him a good target.

Now, where does this work best? Well, I'm sure other Pro's have their own strategies, but here's what I do. Get to level 2 however, the T1 arena is probably best for this. Then go get some darts, and some sort of light source would be nice, like a torch, or if you can afford it, a glowstone. Then go back to the arena, and go down. You're now in the dungeon. Head west, then southwest, and then south. You'll find the Minotaur I mentioned earlier. Stop in the room just to the north of him, and throw some darts at him. Once you run out for darts, run into the room he's in and youll see them all laying on the floor, type "g all" for get all, and then run north again. Sometimes he'll follow you, but usually he wont. Then throw the darts back at him. I did this for 1 level, and then i was able to kill him without the darts, just run in there and hack/slash him to death. So depending on what character you've made, this could be a good starter until level 3, maybe 4. You can also head outside of town and throw some darts at the griffon. He's a pretty good target too. After that becomes trivial, i'd head to the Sorceress, but really, if you can get out to her earlier, itll be all that much faster for you. She gives great exp to low level's. Her tower is off te southern side of the Forest. Its pretty easy to find if you use a map.

Here's a trick to the dart trick. On some older version's of TA, there's a bug in the game that doesnt allow you to drop more than x items in a room. Actually that's in all version's of TA, but that, along with darting, in some version's of TA result in a limitless supply of darts. What happens is this. When you throw a dart, it ends up on the floor of whateve room the creature you're darting is in. Well, once the floor is "full" its supposed to start destroying the darts as they fall to the floor, so after you have 9 or so darts on the floor, the new ones you throw just dissappear after hitting their target. With some versions, instead of dissappearing, they return to your inventory. So you can throw them again. Pretty neat trick. :D

Heartstones:
Normally, heartstones are used to teleport you back to the temple in T1 at the cost of some EXP. Its sort of like dieing, without the death part, you keep your items, just lose exp as though you had died, and go back to the temple as though you had died. Thats all well and good, say you're allllll the way at the bottom of the stoneworks, and just dont feel like walking all the way back home. Use a heartstone and you're there.

There's a bug however, commonly called the "Heartstone Bug", for obvious reasons. You need at least a second player to do this, and they're going to end up losing some exp, and sitting around waiting for you to finish up all night. Usually this other player will be a friend who doesnt mind the loss of progress, or a higher level player who can afford to waste one night and lose a little exp. Basically, you use the heartstone to confuse a creature. here's how it works. We'll call the heartstone player "Player A" in this example, and the other player (the one that will actually benefit from this) "Player B". Player A walks up to some high level creature, does whatever they need to aggrivate it enough that it will chase them, all the while Player B sits in some other room. Player A then walks to the room where Player B is sitting, and just before the creature follows them into that room, they use the heartstone. Player B see's Player A vanish, and then the big nasty walks into to the room. Here's the good part. Player A is sitting at the temple, Player A must REMAIN AT THE TEMPLE! While Player A is at the temple, the creature simply walks between the room that it just saw Player A in, and the room that Player A hearted from. In the meantime, Player B sits in the same room they waited in, and the creature walks in, and out, and repeats that until either Player B breaks the bug (by following the creature) or kills it. As soon as Player A leaves the temple however, the bug is broken, and the creature will probably kill Player B for being in its way.

Groups:
This requires some help from your friends. High level Hunters, and high level Sorcerors have the capability of adding high level creatures to a group of players. Hunters can tame them, and Sorcerors can summon them. This has its advantages. Obviously this means that you can go out and kill things, with the help of say... a dragon. Or you can summon or tame a bunch of lower level stuff to use a fodder during battle. The more targets there are, the less chance you have of getting clobbered.

Heres another perk however. While a creature is tamed, it wont attack those who are "Friendly". In other words, if you're level 3, and in a group with a level 20 hunter, who's got an Elysian Dragon for a pet, the dragon will not attack you, unless you leave the group, or attack the dragon. So how does that help you gain experience? Remmeber, the dragon wont attack you if you're a member of the group. This takes some quick fingers (or a nice macro/trigger setup). Start out as a member of the Hunter's group, along with the Dragon. Then, in as quick a manner as you can, leave the group, attack the dragon as many times as you can, and then request to re-join the group, the Hunter then has to add you back into the group as quickly as possible. So, you got two or 3 attacks off at the dragon, got the experience, and then re-joined the dragon's group before it had a chance to attack you. Remember, while youre a member of the group it wont attack you, and while youre not a member of the group, attacking it wont remove it from the Hunter's group. This will work as long as the hunter keeps adding you back into the group. This exact same procedure will work with a Sorceror, the only difference is that a Sorc can usually summon higher level creatures than a hunter of the same level can tame. This results in better EXP for you.