There is one technique that I rely on more than anything else when teaching swimmers the mechanics of swimming. It's sculling. Most sessions will have at least a few lengths of sculling, whether it's part of a warm-up, cool down or even part of the main set. Learning how your body moves, manipulates, and feels in the water is a crucial part of increasing both your speed and efficiency in the water.
Coaches have gotten a bit lazy in how they coach. Many coaches are just focused on speed work, rather than helping their swimmers become more efficient in the water. We need to change this. We, as coaches, need to be held accountable for the way we train our athletes. We need to provide our swimmers with the foundations of proper stroke technique to help them reach success.