Schedule (in no particular order)

Install Linux if you don't have it already
Install and build Wine sources
Review Riched20 source code (10KLOC, 33KB)
Review Riched20 conformance test (~5KB)
Pick a Riched20 feature to add
Write conformance test for your feature, submit
Review example patch that added a feature to Riched20 
Implement your feature, submit
Keep fixing issues and resubmitting until approved
Get a job based on your reputation as Wine developer
Profit!