The most basic piece of wading everyone should know is how to safely wade the waters you fish. Even in warm water wading water should always be treated with respect.
Fish haven fallen prey to many foes both aquatic and terrestrial. Martins, herons, eagles, bears, raccoons, gulls, otter, mink, muskellunge, pike, even other fish include fish on the menu. Understand that when you wade. Fish have adapted to being flighty and aware of the surroundings. Their eye placement allows them to see in nearly all directions and they can move each eye independently of the other. Knowing this it should come as no surprise that your shadow placement should be in your thoughts. Choose the side of the stream that allows your shadow to fall clear of the water. Remember not only does your shadow fall on the stream bed but also bounces back up at an angle and reflects off the surface film of the water. This movement of your shadow will indeed spook the fish out of the hole while your wading up. Even the fish on the dark bottom that you couldn't see holding.
One of the best parts of stream fishing is stalking. Just like a hunter silently follows a trail you should be just as quiet while spotting fish in your stream. Keep your eyes trained for movement and scan slowly the pools, runs, and tails where you expect fish to be. The fish is counter-shaded (light on bottom and dark on top) to avoid easy detections and can practically remain motionless while holding in a current. It takes patience and practice to see these fish. Pause and examine what you can see on the bottom, what usually gives it away for me is the tail fin slightly swaying in the current.
Watching your footing
The line that runs horizontally down the sides of the fish aren't just for looks, thats one heck of an ear. It's called the lateral line system. It's basically a collection of pores infused with thousands of extremely small and sensitive nerves that relay water vibration and pressure such as sound waves or movement. This means while in the water you need to avoid noisy footing. Gravel and rocky substrate can cause loud clicking noises underwater (sound travels 5 times faster underwater) causing you to spook your fish. Stick to sand and silt foot holds and quietly adjust your footing to remain undetected. Stay away from large clunky rocks that rock back and forth, these things make even more noise that gravel!
If you have to pass over noisy stream bed do so to blend in with normal babblings of the stream, walk through the noisy riffle sections.
Fish rest in the darker deeper pools, thats where they generally hold. Wade on the un-cut banks opposite from where these pools will be. You'll spook a lot less fish.
Wear natural colors
As written above, fish can see you. It's also true that fish can see colors. Where colors that match the environment or at least aren't too "un-natural".
Fish will face upstream and against the current; so walk in behind them. This rule does have some exceptions. As you gain experience reading the water you'll understand that there are many current in a stream which means fish holding could actually face various directions. Using the tips above to stay un-detected and stealthy should allow you to get in cast range of a holding fish. When I was younger I always chose to wade downstream simply because it was easier to do. As I learned this tip I caught nearly twice as much fish.