When you are in a one-on-one situation, there is a really easy way to almost always win a hand. If you have the small blind, and call, then the opponent raises, if you raise as well, then the opponent will almost always fold. This might not work as well against Max though.
Decks
Complete the indicated task to unlock the corresponding deck. Grickle Deck Win 18 tournaments
Homestar Runner Deck: Win 6 tournaments.
Penny Arcade Deck: Win 12 tournaments.
Poker Night Alt. Deck: Win 21 tournaments.
Poker Night Deck: Win 15 tournaments.
Sam And Max Deck: Win 9 tournaments.
Team Fortress 2 Deck: Win 3 tournaments.
Steam Achievements
Complete the following tasks to unlock the corresponding achievement. To view your achievements and stats in Steam, select "Community", then "My profile", then "View all my games", then the game and view stats.
Down to the Green: Win consecutive all-ins.
Flush: Win a hand with a Flush.
Four of a Kind: Win a hand with Four of a Kind.
Full House: Win a hand with a Full House.
Kicker Trouble: Win a showdown where you and the opponent have same hand (pair or better) and you have a better kicker.
Rags to Riches: Win a showdown with just a high card.
Rushing: Win three straight pots.
Slow Play: Check a pat hand.
Special Item: Max: Knock out Max after he's bought in with his special item.
Special Item: Strong Bad: Knock out Strong Bad after he's bought in with his special item.
Special Item: The Heavy: Knock out The Heavy after he's bought in with his special item.
Special Item: Tycho: Knock out Tycho after he's bought in with his special item.
Straight: Win a hand with a Straight.
Straight Flush: Win a hand with a Straight Flush.
Triple Through: Win a pot with two or more opponents when you are all in.
Win A Game: Win a full game.
Win A Game, Hard: Win a game on hard.
Tables
Complete the indicated task to unlock the corresponding table.
Automata Table: Win 5 tournaments. This table makes the game black and white.
BLU Team Table: Win 11 tournaments.
Freelance Police Table: Win 19 tournaments.
Fruit Friend Table: Win 8 tournaments.
Max and Crossbones Table: Win 17 tournaments. This table makes Max a skeleton.
Max Imp Table: Win 1 tournament.
RED Team Table: Win 7 tournaments. This table makes Heavy wear a dealer's visor.
Strong Badia Table: Win 13 tournaments.
Team Fortress 2 Table: Win 14 tournaments.
Telltale Games Table: Win 4 tournaments.
Telltale Shield Table: Win 20 tournaments. This table unlocks all table effects.
Trogdor Table: Win 2 tournaments.
Twisp And Catsby Table: Win 16 tournaments.
Videlectrix Table: Win 10 tournaments. This table makes Strong Bad 32-bit.
Team Fortress 2 items
Eliminate the indicated player when they use collateral instead of money to buy into a hand to unlock the corresponding item in this game and Team Fortress 2.
Dangeresque, too?: Eliminate Strongbad.
The Enthusiast's Timepiece: Eliminate Tycho.
The Iron Curtain: Eliminate The Heavy.
The Lugermorph and The Liscence to Maim: Eliminate Max.