Value Bet the River
Something many new players do wrong is check back their value hands on the river. I'm not entirely sure why they do this, but it probably has to do with an irrational fear that they are re-opening the betting and might get pushed off the pot by the shove of a villain holding a worse hand. These newbies are content to see a showdown and win the pot at its current size. They don't seem to care about the extra value that a river bet provides. Don't be one of these people!
The simple truth is that at mid-stakes and below, most villains do their bluffing on the flop and turn. River bets tend to be real; if a standard villain makes a big bet or shove on the river, he usually has the goods. Or at least thinks he does. What this means is that his bet will give you a near perfect read-- i.e., if villain re-raises you, you're probably toast and need to fold. If he doesn't, then the extra bet means extra profit. This is the essence of so-called thin-value "bet-folding" the river, and it's a bread-and-butter play for professional poker players.
The key here of course is having the ability to fold when re-raised.
Let's repeat that for clarity: thin-value bet the river as much as you can, but only if you are capable of folding when anyone less than a bluffing maniac re-raises you.
Said simply, you have to learn not to be afraid of betting thinly on the river for value--and also have the discipline to fold to a re-raise. Many amateur players struggle with this idea because they just want to see the cards turned up. They say things like, "the pot is big enough." By doing so, they are also saying that they are scared of being bluffed off what could be the winning hand.
If you can come to terms with the fact that people bluff very rarely on the river, then you will start to see your overall game improve drastically-- and your profits go up accordingly.
All-in for now...