Looking at the commits and Github releases for previous versions can provide an example.
Bump the __version__ in __init__.py.
Bump the version in VERSION, __version__ and __notes__ in __init__.py, and VERSION in setup.py.
Update CHANGELOG with a summary of changes since the last release. git shortlog can be helpful to see what commits have occurred.
Also update New Features in helptext.py. This help section has ended up falling out of date. If it isn't kept up to date, it should probably be removed.
Create a release through the Github website, tagging the commit that should be released. The text from the CHANGELOG should be copied to the release.
For mps-youtube, a .exe file should be built with python setup.py py2exe under Windows. Make sure the correct pafy and youtube-dl versions are being used, since they will be embedded in the binary. Attach this file to the Github release.
Push the source, and a wheel build, to PyPI. Be careful that everything is correct at this point; PyPI does not allow replacing an uploaded file with a different one of the same name.
The .tar.gz signatures for pafy and mps-youtube also have GPG signatures attached to the release. Currently, they are signed with @ids1024's key, so only he can perform this step.
The New Features help text isn't really important, but it is genuinely nice to have if kept up to date.
Perhaps the CHANGELOG file isn't really needed, if Github releases includes that information.