You should never bump. Community (the Stack Exchange bot) automatically and randomly (fairly) bumps older unanswered questions (questions with zero answers or questions with no answers with a score >1).
If you haven't received an answer you think is suitable, you can refine your question by editing it. Everyone is encouraged to make substantial edits to improve their posts, for example:
Do some research and document how that didn't solve the issue.
Time has passed and it's possible new information or new sources are available. Add links to information you find elsewhere and document what you did and how this doesn't solve the problem for you.
Community doesn't bump questions with an upvoted answer, as this potentially indicates that the answer was found to be useful. If this isn't the case, that would indicate the question may be unclear and imprecise, or a misunderstanding took place — either way, editing the question to resolve this would be necessary to ensure the question is sufficient in describing the problem. Comments are ephemeral: don't just leave a comment on the answer describing a further complication to the question, edit the question.
Add version details to explain the range of OS or apps with the issue.
New versions of OS may have been released in the meantime. Did this update change anything about the problem? If you've got the same problem with the next point release, that's perhaps not worthy of editing. If a (point) release made the problem worse or changed the symptoms, that's useful information that might help solve your problem, or at least find your question through search keywords.
Trim extraneous details in the question
Shorter posts with a single clear request are far more likely to get new answers as it's easier to see what's being asked for directly. Don't let brevity overcome the question and avoid a question looking like an XY problem, but make sure everything in the question relates to the question. If you're providing code, make sure it's Minimal, Complete and Verifiable.
Share your question using the share link under a post. This provides a handy short link for posting elsewhere, such as on social media, which can help promote it to the audience that can answer.
Bounties are the designed method to attract more attention to your question and this far exceeds the promotion from being on the front page for an hour or so depending on traffic. For more information on how bounties work, see What is a bounty?.
Tumbleweed is a badge awarded you if you've ‘asked a question with zero score, no answers, no comments, and low views for a week’. Some people like myself browse the Tumbleweed badge page to see questions which may have fallen through the cracks and edit/answer if possible. This can give questions a boost they may have not had the opportunity for before.