Sun Tzu's Art of War and Taijiquan Part 2

"Attack that which he must defend." When your opponent attacks, the first priority is to ward away his force. Next comes counterattack. Now, sometimes that is difficult, especially if you have trouble using his force against him. For example, his force is also very soft, so you find it find any force to use against him. What you can do then it to make him react, make him use force, by acting in a way in which he must response. For example, if your opponent is pushing you, with his hands at your elbow and wrist, one way is to use a bit of force at your elbow, baiting him to change the force he is using on each hand (change his 虚实). Once that happens, you can then take advantage of his lighter hand to move in. If he reacts and his lighter hand becomes the heavier hand, you move in on the other side instead. This allows you to slowly gain ground.

"Know yourself, know your enemy, and a hundred battles you can fight without worry." Knowing yourself comes from practising routine, in which you learn how to relax, how to shift your weight, how to maintain your balance, etc. Knowing your enemy comes from being able to listen to his force, which of course is the result of practising pushing hands. Only with these two will you be able to meet opponents with confidence each time.