There are many ways you can go about creating a WordPress theme: you can develop a child theme based on an existing theme, you can work from a WordPress framework, you can build from a blank theme, you can start entirely from scratch…
There isn’t really a best way to go about it, though I’d argue there’s a best fit for each specific situation. In the case of my final project, I decided the most appropriate solution would be to build from a blank theme.
I didn’t have the time to look for an existing theme that I could modify, nor did I have the money to purchase one if it came at a premium. Frameworks can be nice, but sometimes they come with a learning curve, and sometimes they’re overkill, bringing all kinds of functionality and features that you really don’t need. Starting from scratch would have taken time I didn’t have to get the skeleton of the back end all set up. Blank themes provide the essential files needed for a WordPress theme, but without any styling or added functionality. They could leave a little too much to be desired for much larger projects, but they’re perfect when you need to get move on with a fairly small site.
I found one for free on the Lifehacker website, and I added it to my WordPress installation as a totally new theme. I started building from there.