There are many ideas about how to develop good fighting skills. My experience has revealed the following three principles common to good kung fu practice.
Good kung fu is both powerful and effortless. Naturally it should be practiced the same way. If there is an uncomfortable strain being exerted anywhere in your body it is because you are doing something that is ineffective. Let this guide your movement. With good kung fu the more effortless your movements feel to you the more forceful they will feel to anything you touch. Do not try to achieve effortless power over time, but rather feel for it every time you practice.
The more you try to hurry the more you will hinder yourself. Take as much time as you need. If you are unable to control your movements with perfect precision it is because they are too fast. It is more important that you maintain an inherently stable structure at each moment and let each movement start in the heels of the feet and propagate freely through the body than that your movements proceed quickly. Hurrying makes practice less effective, and thus wastes time. Only move as fast as you are able while still maintaining the feel of effortless power and a full awareness of your body’s structure from moment to moment. Also do not hurry to achieve particular results. Instead act as if you have the rest of your life to develop your kung fu and in the meantime make your practice so enjoyable that you are glad to do it for its own sake.
How your movement feels is more important than how it looks. Your own sensations can teach you almost all you need to know about kung fu. You have the singular privilege of having available to your awareness everything you feel. Thus you can sense more easily than anybody else if your structure is stable and if your movement is effortless. An experienced instructor may be able to point out gross deficiencies, but you must feel your own kung fu working. If you devote the time and attention to listen to your body it will tell you how it works best. A powerful movement will feel powerful, a stable stance will feel stable. It is more important to be able to move freely and react spontaneously while maintaining a feeling of power and stability than to be able to do a particular movement exactly the same way many times. Experiment constantly by flexing individual muscles and noting the effect each has on your entire body. Vigilantly seek out and release tension and strain wherever you find them creeping in.
The three principles of kung fu are interconnected. To follow or violate one is to follow or violate all. Straining wears away your patience by making practice difficult and unpleasant, resulting in an instinctive desire to hurry through the motions; furthermore tense muscles make it difficult to determine the intrinsic strength of your posture. Hurrying requires strain and likewise obscures sensation. If you do not maintain awareness of the information your body sends you it does not matter how quickly or slowly or hard or soft you practice, your progress will be miniscule.