Do NOT get in the habit of checking on the river simply because you have a good-but not unbeatable-hand. This is another huge mistake that mediocre players frequently make. If you think you had the best hand on the turn you should almost always bet the river, unless the river put a four-flush or a four-straight on the board. Example: you have K K, and the flop comes Q T 7. You bet and get two callers. The turn is the 5. Again you bet, and again the same two players call. The river brings the 6.

Definitely bet here. If someone had flopped a flush draw there's a good chance they would have raised earlier on which means it's less likely that 6 has made someone a flush. Also, just because a low limit player calls the turn or river doesn't mean they have a big draw. You could easily be up against a hand like J9 and a hand like Q 8. Bet your hand, and collect from the queen.

This dynamic changes if there are four or more players at the river. With three or less, bet just about any hand that was worth a bet on the turn, providing the river wasn't too terrifying. Against four or more, however, you have to start worrying about the flush. After all, it's unlikely that everyone has either a Q or a T, and in a game where players will often play any two suited cards before the flop you have to keep an eye out for a flush when the third suited card hits. Against one or two players, however, and often against three, we go into 'auto bet' mode on the river. If we liked our hand on the turn, then we like it on the river. It's as simple as that.