→Push your changes to your clone on Gitorious
Next select the commits you would like to include in your merge request and click "Create merge request".
Note that it usually doesn't suffice to just send a merge request (unfortunately), but that you'll often also need to "ping" 1-3 core developers who have previously worked with the subsystems affected by the patch (and send a reminder once in a while).
It makes sense to watch the forums/mailing lists or just the git history to see which developers are currently active. To get a list of people who have previously worked with the affected subsystems/files, just take a look at the commit log of the corresponding files and get in touch with the developers via the devel list or forum.
Also, it may help to send a follow-up (merge request review) via the issue tracker here: https://code.google.com/p/flightgear-bugs/issues/entry?template=Review%20request
=== Commit the changes into the GIT ===