chickenwingprin

First of all, it depends on the cut and the quality of meat. If the quality is poor, the best u can do is to marinate it to tenderize it. But you lose the texture and taste.

Assuming we're talking about beef. Make sure you cut against the grains (see http://www.youtube.com/watch?v=0kB_Gl_8v-4. Yes, Yan is annoying. Just fast forward to 3:20). When marinating, mix in all the ingredients. At the end, add some corn starch. It acts as coating sealing in the meat natural juice. Also, if you're stir frying, cook in high heat. Just sear the meat, again to lock in the natural juice.

Similar idea applies if you're cooking steak. Sear both sides at high heat. I once saw in great horror that my friend pressed hard on the steak, squeezing all the juices out. She kept saying, "there's still blood coming out". OMG. Do NOT do that.

For chicken, yeah, I agree. Try chicken thigh. They're cheap. Chicken breast by default is more "hy" due to lack of fat.

Hope that helps!