The secret to a good sear is to remove as much surface moisture from the protein, and make sure the oil is damn near smoking. Also, leave the meat alone! It will let you know when it's ready to flip over. If you start poking at it, and it's sticking? It's not ready. If it moves around or releases with minimum effort, it's ready. Now that you know those basics, you shouldn't have trouble getting a wonderful color and crust on your fish, chicken, or steak.