You don't need tells. Easiest way to win is bid high before any cards are played. Harry will almost always fold unless he thinks he can make a straight or a flush. Borris will be random. Ted will check (especially if everyone else has folded) and at least see the three cards. Grandma only ever puts in if she has something.
Then keep raising. Most characters will wind up folding before the end you get the pot without showing anything. Keep doing it and even if you wind up losing cash when the blinds go up you get it back heaps quickly.