If you are last in position to act it means you have more information available to you to make a decision and hopefully will be able to make a better one. The players acting first are at a disadvantage as they work from incomplete information regarding their opponents and have to take the initiative themselves.
A well known negotiation tactic is to get your counterpart to disclose their holding first. When buying a car it's always prudent to ask the salesman "What's the lowest you can go" and to make them name the price. This price might be a lot lower than what you were prepared to offer and now you have an idea of their range. Poker is the same. Acting first is a disadvantage.
Early Position (EP) - Blue seats/Early grey seats
In 6 max, you are in early position if you are 1st to act in a hand. This is also known as "Under the Gun." You should play very solid tight poker in this position. That means no limping in with low pocket pairs. Also make sure to put in a solid raise of 3.5x or more. Raises in EP should generally be bigger than in MP or on the button because it's very unlikely you will take down a multiway pot without hitting a hand in EP. In a situation with a couple of callers where you don't connect with the flop it's usually always unprofitable to fire a C-Bet and your opponents are in a good position to take down the pot.
Unless holding a big hand, you do not want to play all streets in EP especially with a lot of others in the pot.
Mid Position - Grey seats/Early green seats
Players can loosen up a little here, especially if there has been no action before them. However, remain cautious.
When making more speculative raises from MP be aware of the frequency that the CO and Button call and 3Bet pre-flop raises. As with early position, you don't want to be stuck playing a pot out of position against an aggressive player. You will end up giving up or getting into tricky spots too much to make it profitable.
3x the Big Blind is a good amount to raise to in Mid-Position. It allows you to maximise your value and not scare off opponents when you have bigger hands, but doesn't commit players in a later position than you to making loose calls you don't want to see.
Late Position - Green seats/Yellow seat
These are the most profitable positions to play from in poker. It's from the button and the cut-off that you will make the most money. When the action is folded around to you, there are only a few players who can possibly play against you.
Raising from these positions should indicate strength and even if the flop comes you're still in the driving seat, although be prepared to throw some hands away - you can't win them all!
Raising from these positions should be anywhere between 2.5x - 3x the Big Blind. Look out for the blinds 3Bet percentage: If it's high you want to protect yourself against playing big 3Bet pots with marginal holdings. A 2.5x raise will achieve this and if effective stacks are 100bb's it sets your opponent up to either be exploited by having their blinds stolen too much or by regularly playing reasonable sized 3Bet pots out of position. Another way your opponent could adjust is by ignoring the 2.5x raise and 3Betting to an amount that should scare you off. By doing this they are giving up a lot of value by forcing folds when they have strong holdings and creating a situation where it's profitable for you to fold a good number of your raises and wait to play a big pot with a strong hand.
More information can be found in our Playing The Button article.
Even with a solid grasp of the fundamentals of table position it's important to gauge your table image and adjust accordingly. If your opponents are beginning to get tired of being bullied by you on the button then it's time to tighten up - even if you're getting some marginal hands you would sometimes raise. Conversely if you're viewed as being quite tight and it's obvious this is being exploited, it might be time to put in some 3Bets in late position and raise a bit more to take advantage of your tight image.