When the number of players drops to 3 or 4 then statistics dictate that no one gets good cards all the time. He must be bluffing at least 50 - 60% of the time - or he's very lucky. With so few hands, even Queen of King high can be a good cards. I'd be inclined to raise before the flop with these cards and then slow play better hands - high pairs, AK, AQ, xxs etc and hope the bluffer raises when you hit something, then you make him pay big time as your playing no limit.

You also have to mix your play up a bit. If you only bet when you have a hand he will always be able to dodge you. Put a few bluffs in yourself, it might cost a few cents but the other players will not be sure where they are at with your betting. Gotta keep 'em on their toes!

If your playing just one on one then you may need to be a bit more conservative. If you play very loose they you may get cleaned out in just one hand - so a bit tighter in this situation. If you have more cents than the other player (ie twice as much) then put pressure on him pre flop (i.e raise) as he'll be waiting for a premium hand to play. This mainly applies to games with blinds before the cards are dealt as blinds eat away at players stacks forcing them to play something sooner or later. I suggest you should start playing this way as its an integral part of Texas Hold 'em - especially as the blinds get bigger later on.