On the River - No Limit Texas Holdem
1. Avoid betting unless you are quite sure to win a showdown, especially when facing tough opponents. You have little to win and a lot to loose (as you 90% of the time will only get calls from players who believe they have your made hand beat)
2. Try to figure out your opponent/s most likely holding/s and bet the amount you suspect they might call.
3. Sometimes check a good hand in order to induce a bluff from someone who you think missed a draw, since they will not call your bet anyways.
4. Often you should bet small when having the best hand (and no scare card hits on the river). This amount will entice players to call with a weaker hand.
5. When you have hit your (nut) draw, often bet 80-120% of the pot to make it clear that either you made the draw or you are bluffing. This kind of bet generates almost as many calls as a small bet.