Andrew Nacin, one of the lead developers of WordPress, posted an excellent read on how to best contribute to the WordPress project, as well as some information on how core committers (that is, people who have access to commit code) are chosen.
You may not see it right away when you start out as a contributor, but it’s important to place the project’s goals ahead of your own. You might have reported a dozen tickets and it’s possible you disagree with how ten of them were handled. You can and should work to fix tickets you reported, but at some point, you’ll hopefully run out of those and need to look elsewhere to get your fix. Many contributors — including every committer — have “wish lists” or “pet projects” or “pet bugs” that they still haven’t gotten to, because they realize the project isn’t ready for them, or because their solution isn’t ready for the project, or because it simply isn’t a priority.