The step for Jillian Tamaki to uses, she suggest us come up with some ideas, looing something interesting. It can something around you or some experience  with the daily life. And then, collect those idea together, you can collect form internet, or newspaper, or magazine, or use dairy to record . be  careful to look for the source. Find the key word or use your own word to help you understand that. Mark down something is interest to you. Also you can look for the photo as reference to help you create the thumbnail. After you finish that. You can refined your word step by step . I learn some technic is before to start the thumbnail, write down some key word is helpful to create the thumbnail and organize the idea. Also, reference photo is helpful to refine your work in detail.