Dive right in. Write the bare minimum that you need to demonstrate the uniqueness of your project and then get feedback on it immediately. It's good to have s

Dive right in. Write the bare minimum that you need to demonstrate the uniqueness of your project and then get feedback on it immediately. It's good to have some high-level ideas of what it could be, but don't waste time with formal documents. Wireframes are pretty useful for making any web page, not just a hobby web app. My process is to sketch out wireframes, make the HTML and UI, then build the backend. Also, I try to come up with at least three ways to implement a UI for a new app. That way you don't get emotionally tied to the first one just because you thought of it first. Usually, I find that my first one is crap, and the second one is good enough that I never can think of a third one that's better than the second.