Table position is basic.
There are a variety of articles out there describing the Texas
Hold'em starting hands and how best to play them before seeing any cards on the board or pre-flop and how best to play them after seeing the first 3 cards on the board and after or post-flop. But I think what gets omitted or perhaps not emphasized as strongly as it should be is the concept of POSITION. Your position on the table dictates how you should bet a certain hand or even if you should bet a certain hand.
The table is divided into three basic postional categories. Early positon when you are generally one of the first to act. Most often the BigBlind and SmallBlind are included as part of early position. Here, the problem is if you limp in with a drawing hand such as 7-8 suited, there are still 6-7 people yet to bet after you. They also describe it as there being 7 people behind you waiting to bet.
If you get a large raise from one of these later players, you will be forced to fold your bet -- hence a net loss in chips.
In the middle position, a player can play little bit more loosely than when betting in early position, as the number of players to follow is decreasing.
Finally, from late position, particularly when you have the dealer button and are the last to act, you have the advantage of seing how everyone before you acted. You will always be near the last one to bet on every betting round. This allows you to play you drawing hands and others without fear of getting pre-empted by a large raise after you.
Give this concept a lot of attention. It is not particularly difficult to understand. However, it allows you to maximize your and also is instructional on how to bet them. Each chair on the poker table on a given hand is not equal.