Class 1: In this class, points are high, but games are reletavely long (how long depends on your's and your opponent's play speed), because there are a lot of low * cards, meaning low dmg. 16* decks are recommended for skilled players who are capable of winning 3-4 rounds. 18* are little improvements on 16*, and are also pretty good if used right. It is emphisized that here you need to PLAY QUICKLY if you want a chance at first place. The *s are low, so there isn't a lot of heavy hits, so you need to play the rounds fast. 16-18* decks are used to implement the pts per less star bonus. 21-23* are for those who want to play it safe, though you better play a bit faster. With not a lot of 2HKO's going aroung, this class is basically for those smart UR DT players.
Class 2: Here, 2HKO decks rule. Usually, a good deck will have several 2HKO options. 24-26* are for the pts per less *s bonus, 29-31* are for the less confident players who want quick 2HKO games. There is more dmg than Class 1, but still pretty much about strategy.
Class 3: NOT RECOMMENDED. You can use a very fast KOing 32-34* deck, but it's no stategy, just brute force. Plus there are those mission-people, stray DM decks, and leaders. You can try, but generally the DT winner is usually from Class 1 and 2.

Penalty Cards: These are the OP cards that the UR staff has put penalties on. Basically, if you win with them in your hand, you have to face a penalty. I won't list the penalty cards, but generally, it's better not to use them. There are -2 penalty cards, -5 penalty cards, and -10 penalty cards. You can MAYBE use one game-changing -2 penalty card, but -5 and -10 cards are OFF LIMITS.
Other cards you should stay away from: DRs, Pill Manip, poison, heal, +life
DRs: They slow down the game. In DTs, you need to play FAST. DRs may help you win, but it's usually better not to use them as it stalls time. You MAYBE might use one, but that's it. This is the reason why Pussycats can't be played in DT, because they play too slowly. In Class 2, it is better to drop the DRs and just get 2HKOers, and in Class 1, the dmg is already low because the *s are low.
Pill Manip and +life: Not as much as DR's but pill manips and +life can also slow down the game. Your opponent may go like 'Oh mah goodness, is he going for it, is he bluffing, or is he anti-anti-bluffing, or anti-anti-anti-anti-bluffing or is he...' and take forever to play. Don't use excessive amounts of these cards, but a little is okay.
Heal and Poison: The problem with poison and heal: They take time to activate. In Class 2/3 where it's all 2HKO's, this is a problem. They also both somewhat take some time to think about, which will slow the game down. U might consider them in class 1, but in the other classes, it's not recommended.

Remember, you need to give your opponent the easiest time to make his decisions before you beat them down. Let them play quickly, them destroy them for points.
Clan Choice: Class 1: A clan that have good 2/3*. This is important: they all need to be able to win. Solid stats usually isn't enough. Keep that in mind.
Class 2: Good cards that can somewhat 2HKO. The best are clans that have bonuses that can help them win and have good 2HKO options (*cough*Uppers*cough*, *cough*Montana*cough*). Remember, this class is all about quick games.
Class 3: Any clan that isn't mono Freaks or Pussycats can do decent.
Like with all decks, look at your worst hands, best hands, decent hands, solidity, 2HKO's, counters, etc.
Remember, NEVER QUIT A GAME unless you want to quit the DT. Accept a loss and move on.
If you are going to lose, then remember to do so quickly, so you can move on and get another match.
It may also matter slighty which DT you're going to play in. There are more players in some hours than others, so if you want a little more chance to win, do in a less crowded DT, and if you want a challenge or a better reward, then go find a crowded DT.
Be completely focused, no multitasking, no distractions. I recommend not checking your results, and using the enter/space bar to get into another match.

Now, one HUGE thing that will effect your DT: LUCK!!! What hands you draw, what opponents you face, the real world, ect. It takes luck to get fast games, get good draws, etc. You might think that you got a pretty good DT, but another guy may have had the DT of his life, letting him win. Luck is HUGE. However, even if you play a really unlucky DT, there are always other DTs. That being said, while luck is a deciding factor, experience is also important. Playing more DT's will increase your chances of winning a DT. Now you might be like 'Crap! Is this a bluff? No, it's an anti-anti-bluff! Oh wait! He might predit that!!! WHAT DO I DO!!!', but later you might be like 'Hmm, go, 3 pillz Bob Joby!!!'.
I hope this guide has helped you, and you have reliezed the meaning of life or something. Happy gaming!

Forgot to mention;

Turn off finishing moves. You want to have all the time you can get.

Abuse commonly elo banned cards that don't have any penalty to them, especially in playing 23* and under.
Avola, Leviatonn, X-ODUS, Askai, Troompah, Sylth, Uranus, and Robb are all ridiculously strong, and using them is a big advantage.

Try to win as many rounds as possible..ko in 2 rounds wont give you more than 25-27 points..whatever your deck is(starwise) dont use the max stars allowed cause star difference gives you additional points when you win.. when you have your bad hand you got to pill everything so that you force your opponenets to do mistakes..

"DRs: They slow down the game. In DTs, you need to play FAST. DRs may help you win, but it's usually better not to use them as it stalls time. You MAYBE might use one, but that's it. This is the reason why Pussycats can't be played in DT, because they play too slowly. In Class 2, it is better to drop the DRs and just get 2HKOers, and in Class 1, the dmg is already low because the *s are low.
Pill Manip and +life: Not as much as DR's but pill manips and +life can also slow down the game. Your opponent may go like 'Oh mah goodness, is he going for it, is he bluffing, or is he anti-anti-bluffing, or anti-anti-anti-anti-bluffing or is he...' and take forever to play. Don't use excessive amounts of these cards, but a little is okay."


BLASPHEMY!
Polly Met a Cat

though it may make sense to play fast 2ko decks over 4 turn decks, it should be noted that most people running in class 2 are usually going to be running some form of 2hko dependent deck so denying that can ruin their deck strategy

Also remember the age old DT mantra "Win fast, Lose faster", if you know you're going to lose a fight let a 2hko through asap or you will just be wasting time, same goes for stallers, most times its better to lose to 1 staller and win 2 more after him than just play 2 battles with the staller.

P.S
when a battle starts at dt take a good look at all the cards(including the opponent's)..If you have a hard time winning more than two rounds then aim for a quick ko..

Is it easier to play in Standard?