Poaching is definitely a skill that almost all players need to play good doubles. It involves many factors including communicating with your partner, anticipating your opponents tendencies and quick decision making. Here are a few tips to use on the court.

1. Being an active net player is definitely the way to go in doubles. Effective net players tend to bother their opponents with the constant movement and occasional poach.

2. Poaching falls into two categories: anticipatory, or the total "sell out." The anticipatory poach is executed when you judge that your opponent is limited in his or her options and you anticipate where the ball is likely to be hit. The "sell out" poach is when you are going no matter where the ball is hit or what position your opponent is in. This is obviously the more dangerous poach, but can be very shocking to your opponents as it is usually very unexpected.

3. If you have a regular partner, consider developing hand signals that let your partner know you may be poaching when he or she is serving. 

4. Don't get frustrated if you get burned down the line a few times. It happens to everyone and should not deter you from continuing to be aggressive.