Note: This will satisfy the requirement for Scrap 3 of Walton's Gang outfit. First put on the Elegant suit(the one which lets you cheat in Poker. Go to Poker room in the back of the bar in Armadillo. Play a game and Cheat BUT LET THEM SEE YOU CHEATING. This will make you duel. Kill or disarm the player that challenges you for Honor or Fame.
After that there will only be 2 players left at the Poker table, play again and get caught CHEATING again. you duel again. On the Last Poker Player I'd advise NOT to cheat -- the last player is fast and catches you cheating easily.
Now you'll be playing 1 vs. 1. Use this pattern to win: Check or Call THEN Raise and the Opponent will Fold Every time. If you want the game to go faster and BUST the opponent out. On your First hand, raise then check or call then raise.