One of the first steps when writing any piece is the generation of ideas.
This is called pre-write and there are many techniques to help you come up with ideas for your writing. Two of these stages in this process are free writing and branching technique.
When free writing you simply write whatever is on your mind about or around a certain topic or idea. Because it is important to organize your thoughts and ideas. Branching helps as a first or second step. It a more visual system where you pick a topic and branch it out trying to make it more specific. For instance: Animals wild /domestic.