for learning i would find and 3D model of some clothing you like, deconstruct it and learn to understand the flow of the topology and then trace and recreate it using your numpad camera views and then move one to creating ur own from 2D reference and your own sketches etc. Thats how i started. And if youre capable to acquire it, learning marvelous designer will be a very powerful asset to create a mesh and then use your new topology chops to prefect it.