I agree with davidkallman. I don't think your project should focus on HTML. If it did, you would need to examine its structure as a formatting language, compare it to alternatives, make some changes (that would be a challenge!), etc.
If you are interested in something having to do with web pages and HTML, try to think of a problem that could be approached or solved with HTML and related technologies. For example, a web site that people could use in which they enter some kind of information, the web site does something useful to it, then presents the user with the results. This would be a software engineering project.
The interesting parts of that would be 1) deal with a problem that people need or want to solve that can be solved by a relatively simple program, 2) design, build, and test a computerized tool (a web page/site) that does it.
) and possibly PHP (http://php.net/
), if you want to write a program that does some amount of calculation.