Here you go...

XP scales down nicely since it is optimal for small focussed teams.. 

- You can create a spreadsheet of feature requests, prioritize them & pick the top-most one.
- define the acceptance criteria (what done looks like) and code it up into a executable test
- Next define engineering tasks to get to done
- Write unit tests, do the simplest thing (YAGNI) and refactor all the time. The goal is to make the outer acceptance test pass
- Timebox each session. For effective time-management, you could also look at [the Pomodoro technique][1]. 
- Use version control & Setup a CI server / a batch file to create a install or zip of your software
- Demo frequently. Route the feedback into the original spreadsheet and reprioritize

The only thing that you couldn't do in a team of one is PairProgramming.