If you don't have a lot of experience with submitting patches or PRs (pull requests) to an OpenSource project please start by reading the Contributing to Open Source Projects document. (It's probably a good idea to review the document even if you do have experience, just to make sure that you're "on the same page".) The document provides a clear and concise set of general guidelines for contributing to projects which will help streamline the process for both you and the project maintainers.
If you don't have much git and GitHub experience then you may want to review some appropriate tutorial, reference or other help documents before you dive into the deep end of the contributor pool. You should have at least a conceptual understanding (and know how to find the details when you need them) of things like github forks, git clones, branching, merging, local and remote repositories, upstream repository, pull requests and issue tracking at GitHub, and so on.
Here are a few resources to help you get up to speed on using git and GitHub, be sure to google for more info when you don't understand how to do something:
The rest of this page will simply emphasize a few of the important things, building upon the guidelines in the Contributing... document.
If your contribution is intended to fix a bug or other issue, make sure that there is a GitHub issue created for it. If there isn't, then create one. This is not necessary for enhancements or new features.
If your contribution is large or complex it may be a good idea to discuss it first in the GitHub issue or on wxPython-dev. It may save you some work and frustration if your contribution may need to be implemented differently than what you had in mind, or etc.
Always create a new branch for your contribution, do not use your master branch as the source of the PR. Why? Two reasons: Because everybody has a branch named master, so giving your contribution a different name eliminates that particular confusion. Secondly, if you use your master branch then that means that you should not make any other unrelated changes to your master branch until after your PR has been merged.
For example, to create a branch for a feature that "foos the bars":
<Do a fork and clone of Phoenix if you haven't already...> $ git checkout master $ git pull $ git checkout -b foo-the-bars <hack hack hack> $ git push origin HEAD <submit PR based on your 'foo-the-bars' branch from your GitHub fork>
If there is an issue associated with your contribution, then include the issue number in your PR's description text, (for example, fixes #1234). This will cause the issue to be automatically closed when the PR is merged.
Do not put more than one fix/feature in the same branch or PR. Make a new distinct branch and PR for each of them.
Test. Test. Test.