Fashion is passion. That is the main reason why it is easy to sketch. However, when the passion is simply repressed, we really need brilliant idea on how to fashion sketch. Thus, as idea may flows anytime, prepare your drawing paper, tracing paper, and pencils. You can also have eraser, croquets, as well as colored pencils.
Then, after having the stuff prepared, the very first thing you should do is to decide the theme of you passion. Let’s say, you are thinking about winter. Therefore, browse pictures and photos about winter. I would suggest you not to draw any sketch, yet, draw a cartoon or cute pictures related to winter. By doing so, you can really refresh your mind.
The second things that you may try to get inspiration about how to fashion sketch is by hanging out, and enjoy the scenery. At the very first place, you can really cool your mind. Then, you can also meet people, and get inspiration from them.
Lastly, if you are not into going anywhere, all you need to do to find idea in how to fashion sketch is by browsing for designs, as well as reading magazines. Try to look at the clothes any designers has created, and give comments. Then, realize your comments on your sketch. Good luck!