Organizing your content will probably be done in phases.
In the beginning, try to anticipate the types of media content, what are generally referred to as assets, as possible. For example: you know you are making a video project, so start with a project folder where you will keep the various versions of you project. Each project is unique, so the folders you create for storing your assets may change, but over time you will develop a list of project folders that you commonly use. Here is an example of how I generally start organizing my content.
I have found that it is impossible to anticipate the categories you will need in the beginning of the project. Take time about half way through to reorganize the files to better represent the nature of the project.
Having a good file structure will also save you lots of time on the backend. You might be able to easily remember the details of a short of small project while you are working on it, but if the project gets more complicated or time passes between sessions, it can be very difficult to remember what you named the files or what folders you put them in.
I generally start my files with a date: year/month/day, for videos or photos. That way the files stack according to when they were created. The year first is really important especially if your project spans multiple years. Next, I identify the type of media (video, photo), and finally some sort of unique name that might describe what the media represents.
Other media I start with the type of media and then some unique identifier.
Some people prefer an alphabetical system. I don’t, because that means that I have to remember what I called the file folder the day I set it up.