Watch cooking shows and read cookbooks, but most importantly get in the kitchen and actually do some cooking. Lot's of people become "Armchair Cooks" similar to "Armchair Mountaineers". They create this fantasy world in their heads where they see an Iron Chef cooking twelve components at once and think, "Yeah, I could pull off at least 3-4 components to a meal - heck, it's just mixing flour and water!". At some point you have to dive in and learn by making mistakes.
For a direct approach, you can search out local cooking classes. For a formal approach (that works well for some), purchase a textbook used by a cooking school (such as the CIA) and follow along in the kitchen. These methods can get expensive unfortunately. If you do look for cooking classes, choose between them based on their level of abstraction. If they are advertised as "French Fusion" or "Chinese", avoid them. Look for classes that focus on technique, such as "Braising" or "BBQ Fundamentals". Learning technique rather than a specific recipe will open doors to thousands of recipes for you to try at home. It's similar to the "Teach a man to fish..." metaphor.
Oh, and spend time with friends/relatives who can already cook well. Ask them to show you some things. This is probably the best option by far.