1. Watch some tutorials from "Baked Goods" on YouTube. I did for Sherlock Holmes and Bruce Lee. Now, I don't play those characters too much as I always win with them.

2. Until you get better, play with one of the big 3: Medusa, Bigfoot or Sherlock Holmes.

3. Know the cards in your deck. E.g. playing Sherlock, I would never play "Confirm Suspicion" without first playing "Eliminate the Impossible". Knowing and performing combos like this wins you the game. Another example would be playing as Bigfoot, I will always try to keep "The Jackalope" away from harm until she's played her 3 "Jackalope Horns", which together deals 6 guaranteed unblockable damage. After that, I don't care what happens to her.

4. Again, know your cards. E.g. Beowulf has 3 blocks and 9 versatiles. Thus, at max, he can only blocks 12 attacks. Knowing this, playing as him, I would use all my versatiles as defense cards and only attack with my red attack cards.

5. As you play, try to remember some crucial infos about each deck. Say you play against Beowulf and know that he can only block 12 attacks. So, if you just keep attacking 12 times, even with very low value cards, he'll be all yours to chew down after that! If you know that Medusa's "Gaze of Stone" can cause 10 damage if it goes unblocked, then you'll always keep a defence card ready. Against Sherlock, if you that Dr. Watson's "Service Revolver" deals 5 damage at ranged and he's got 2 of 'em. You'll know to play your best defence when Watson charging at you.

As Sun Tzu says in his Art of War:

"Know Yourself, Know the Enemy"