Tournaments are what draw a lot of people to poker, maybe because of the attention they get on television, but sometimes new players are intimidated to try them. Tournaments seem a lot different than the cash games that the new player may be used to. There are a lot of different strategies to tournaments and this only covers a small part of it. A lot of considerations like stack size and individual reads aren't included in the generalizations I make about the different stages of the tournament. This article only talks about the tendencies of the overall table from my experience. Since most players agree that the best way to adjust to your table is to play the opposite of how they are playing. During different stages of a tournament a lot of people generally behave the same way, so recognizing this and playing accordingly is a great way to accumulate chips. This isn't always the case by any means, and it's always most important to observe your table for a correct read on how everyone is playing.

An easy way for a new player to deal with the change is to divide the tournament into different sections and adjust their play for each stage. These are just some general guidelines though. I've separated the tournament in to 6 different sections in to what I feel are the most representative of where a lot of players change gears.

Early tournament:

At the beginning of most tournaments the biggest problem I see by far with people's play is that they play way too loose. A lot of newer players just play too many hands that they just aren't going to win with in the long run. Early in a tournament when most of the players are playing like this, it's important that you play the opposite of the table and wait for solid hands. At this point even if the table is playing tight, the blinds aren't worth stealing. When the blinds are low you can see flops for cheap with speculative hands like suited connectors or little pairs, but it's important not to get carried away and leak away all your chips. Too many players will play any hand or call any raise just because the bet doesn't seem to represent a significant portion of your stack, but all those little pots add up.

Mid to Late tournament:

I consider the mid tournament to be when the blinds start becoming a factor to your stack and including antes and transitioning into the late tournament up till the bubble. This part of the tournament is especially dependant on other factors like stack size and how the rest of the table is playing. Whether you're a short stack and need to pick up those blinds in order to survive, or if you're a big stack looking to take some selective risks as well as the style of play of the rest of the table is going have a very large effect on how you should play during this stage.
Some people think this is a great time for blind steals when in position, and a great time to try to steal some pots as this is when they start to become consistently bigger. The most important thing to remember during this stage and later ones is to not let yourself get too short stacked.

Bubble:

No one wants to lose on the bubble. Trust me, I know how frustrating it can be playing for hours upon hours just to lose before you make any money. The fact is though, that the money you make from just barely cashing is almost always meaningless. The way that multi table tournaments are structured puts most of the prize money in the top 3-5 spots. If you aren't playing to get in those top spots, you'll never be a long term winner. The bubble is one of the best spots to pick up blinds and pots off of the people just trying to squeeze in to the money. You shouldn't just start mindless aggression just because it's the bubble. The goal should be to target players you specifically think might be trying to squeeze in to the money. You'll almost never have a table where everyone is playing tight just to make the money. Usually you're going to have at least one other person trying to steal blinds. Re-raising someone who is stealing on the bubble is another great opportunity to pick up chips.

In the money:

When you just make it in to the money, you usually have a lot of short stacks and people who after having played tight for the bubble, are looking to gamble. Short stacks are looking to get all their chips in and double up, and all those people who were playing tight and felt like they were being stolen from are more likely to push on a perceived blind steal. Depending on the number of entrants you may be transitioning shorthanded tables to full ones because of fewer and fewer tables remaining and being broken up. It's important to adjust to play more hands when you have fewer players at the table and fewer hands when you have a full table.

Final Table Bubble:

In the final table bubble you get a situation that is very similar to the money bubble earlier. When on the bubble you usually face a situation where the table is playing tight so you loosen up. At the final table bubble you're usually going to be in a short-handed situation as well as one where most people are playing tight to try to get to the final table. People playing tight combined with the table being short handed make it critical that you get more aggressive and pick up the uncontested pots.

Final Table:

The beginning of the final table tends to be similar to the situation you're in when you just make the money. There are usually a few short stacks that have been bullied shorthanded and are looking to get their chips in and double up. Although you may be playing tighter at the beginning of the final table, once it starts getting shorter-handed it's important to remember to get more and more aggressive and really play for the win.