Before you begin to marinate, keep these tips in mind.
DO make sure your meat is dry before slicing and marinating. If you wash your meat before cooking, make sure to blot it with paper towels until dry. Water is not a flavor enhancer and will only serve to dilute flavor and make browning more difficult.
DO marinate your meat in a bowl that's big enough for mixing. You don't want a bowl that just perfectly holds your sliced protein. You'll be mixing ingredients around, so make sure you have room for the meat to move.
DON'T add minced aromatics to your marinade, like garlic, ginger, or scallions. Stir-frying is high heat cooking, and those minced aromatics rapidly burn. Instead, add them toward the end of the stir-fry. Alternatively, you can slice them into big pieces and fry them in oil for about 30 seconds. Once you remove the aromatics, you can use cook with that infused oil.
DON'T drown your protein in your marinade. Remember, you're marinating for a stir-fry. Too much liquid as you stir-fry your protein results in steaming, and nobody likes steamed meat, right?
DO make sure to give your protein enough time to marinate. For this marinade, it only takes 30 minutes. Each ingredient in the marinade needs to have enough time to do what it has to do. This window gives you plenty of time to get your other ingredients ready.