What is the secret to perfectly battered food?

Every time I attempt to make batter-fried foods, something goes wrong. Either the batter is too watery and won’t stick to the food, or it’s too clumpy and won’t stick to the food. If it does stick, then it also sticks to the pan when I try to remove the food after frying. Whatever I’m doing, I’m not doing it right.

I don’t fry things often, but when I do, I’d like to make them turn out tasty, light, crispy, and perfect. Can you tell me how? Bonus points if you can tell me how to batter something all the way around, without a gap where I was holding the food item as I dipped it in the batter.