Whenever possible, if you're about to KO an opponent and have attack to spare, leave a pill off for the pill bonus (+2 points). this pays off over the course of a tourney.
Whenever you have multiple kills possible, choose the path that creates the most points for you (eg. kill their 5 stars with your 2 stars, etc.) This maximizes your in-game points.
There's two ways to do well in DT afaik -
1) the Uppers
/2hko way: kill everyone in 2-3 rounds with low starred cards. You'll probably make between 10-15 a match, but if you play fast, you'll be able to get a lot of battles in.
2) control way: kill in 4 rounds, but use powerful low starred cards to create lots of battle points. I use Piranas
in DTs and they do very well. Pill manip usually ensures a +2 at the end of a match, and the Piranas
have a slew of good 2* and 3*s, which equates to good points created. Using this method each fight takes a little longer, but I average a little over 20 points per victory, which is quite good. In some fights where I win all 4, I can get close to 30 points (in tourney).
My other advice would be don't use Jungo
as they slow the fight. Pill manipulation is good b/c often the fight is over after the first round and your opponents play fast to finish. Big life differences and reduction just make the person take longer to add/subtract, and doesn't help you kill your opponent faster.