Hi there. When you do a commit that fixes a bug, try adding a '--fixes lp:123456' to the bzr commit. Launchpad recognises these and automatically link the branch and merge request to the bug report.
This makes it easier for the reporter to see progress. If you forget to update the bug status (such as bumping it from 'Triaged' to 'In progress') then it's obvious that it's being worked on.
See https://bugs.launchpad.net/gcc-linaro/+bug/942307 for an example. The status was 'Triaged' but there's an approved merge request which shows work is being done.
-- Michael