How to make Chinese-style cornstarch coating stick
The key in a stir-fry is that the ingedients can at all times move about freely. A spatula shouldn't really be needed, the way it is in sautéing, rather you use a spoon/ladle to just, well, stir the loose mixture. In fact even that isn't ideal: arguably, it should rather be called toss-fry, because vigorously moving the pan is the best way to keep everything apart, while minimising damage to items like coated tofu.

A proper wok is certainly the best utensil for doing this since its round shape keeps the tossed-up ingredients best from flying out of the pan. I don't actually have a wok, but I find non-stick aluminium pans to work well too, as they can be controlled easily and conduct heat quickly. (Purists will probably disagree here...)
At any rate I wouldn't care to do a stir-fry in a heavy traditional european cast-iron pan. Way too inert.

Apart from that, a couple of conditions are important to allow for easy enough movement:


Not too much finely chopped material or viscous liquid should be in the pan, as both hinders movement.
Nothing can be allowed to start sticking to the bottom.
There needs to be sufficient heat, and enough heat transfer, so you actually get the cooking done quickly.
Not too much water to absorb/vaporise away heat, at least at the beginning. Rather more than less oil helps though, but of course not as much as in deep-frying.


Again, all of this is clearly best accompished with a wok over an intense gas flame, but can also be done without.