Most popular games today have 9-10 players, and where the players are situated around the table is important. The dealer button is the most advantageous position to be in. Every other player's position is relative to the button. With each betting round, the button moves around the table and the other positions shift with it.
The button is the last position to act, and the advantage is that he can see what all the other players have decided to do - bet, call, raise, or fold - before he must make a decision. For example, say you're the button and you aren't holding anything significant. Someone at the table makes a big raise before betting gets to you. It's likely that the person who raised has a better hand, so it's wise to fold on this hand and risk nothing. On the other hand, if you have a pair of queens and no one has made a significant raise, you might have the best hand at the table. The only player actions you can't judge are the mandatory bettors, the small and big blinds. In a late betting position like the button, you can watch the other players and gauge how much confidence they have in their hands. A quick, significant raise indicates confidence - or a good bluff - and a hesitant, small raise or call may indicate either inexperience or a so-so hand. Remember that actions will also give you away to other players. The button has more time to make a decision, and as a result, less pressure.
All the betting action starts with the small blind position on the button's immediate left. Regardless of the cards he's holding, he must place the first bet in pre-flop betting rounds, usually half of what the big blind must bet; we'll get to the big blind in a minute. This means that even if the small blind has the worst possible cards, he's got to put something in the pot, usually half the amount of a full bet. But if his hand is bad, he can fold without risking more when the play comes back around. Small and big blinds are also late positions, and have an advantage.
The big blind is the position next to the small blind. He must make a full bet, regardless of his cards, but he's still in a better position when the play comes back around. Being in one of these positions – button, small blind or big blind – gives you the best opportunity to bluff. If the table is hesitant to bet and making small raises at best, a big raise might scare everyone else into folding, leaving you to rake in the pot.
The early positions are in the worst position from an intelligence point of view. The small and big blinds must bet, so you know nothing about what they may hold. The only information you have is what's in your hand. If you decide to bluff, do it with style and confidence. Make a substantial raise quickly to make the other players think you've got something in your hand. If you've got great cards, fake out the late positions by hesitating and making a weak bet to try to get a raise from the other players. Remember that poker is all about psychology. Being able to convince the other players you're weak when you're strong or strong when you're weak is money in the bank. The middle positions are difficult to work from. You have a little information to work with, but not enough to make an informed decision. Play it the same way as the early positions. You can still bluff, but you're at a distinct bluff disadvantage unless the early players fold. In the middle position, play it safe or make it big.