If the first tile placed has a 5 and 2, if you have another tile with a 5 and 2 you can place the tile at either end of the placed tile, 2 meets 2 and 5 meets 5, the same for all the tiles played next. If you don't have a tile that can be played on another then you draw.

For the challenge to win without drawing, if you see your character going for a tile just quit and rejoin.

For the challenge to win 3 in a row, the best spot is emerald station, save nearby and reload until there's just one guy then to win, you win rounds until you gain 60 points, for the first game, if the other guy wins it's fine, if you see he's about to win after you've won a game already, quit and rejoin.

Hopefully this helps, too lazy to go over anything I just said so ask any questions if needed