There are many options available for joining a mining pool, depending on your preferences. You should make an educated decision on which mining pool to use, based on the payout method, the fees charged, and how often a block reward is found. Other features that are nice to have include statistics, easy withdrawal of funds, and various types of merged mining.
The payout method can vary between the mining pools. Check the method and the fees included to make sure they match your risk and ability to wait for payouts. Depending on your mining operation's availability, the type of payout may affect your rewards. For example, the miners who do not run stable mining operation will be punished using a score based payout. This means that if your miner gets disconnected for some time, your score may drop to zero.
Also, consider the terms for the payout. Some mining pools release earnings automatically, while others may impose a threshold.