I have a question on Stack Overflow that no one has answered after 12 hours. I don't have enough rep for a bounty, so is there any acceptable way of bumping my post? If not, what should I do to get my question answered?
Have you been working on your problem in the meantime? Did you try something that didn't work? Did you find a page somewhere that suggested a possibility but didn't include a solution? Did you debug through the problem and observe some values that were all just fine and so do not explain what is happening? Editing your question to include more information (including links to documentation, dead ends, and things that didn't work) will make it easier to answer and as a happy side effect, will also bump it.
Don't make pointless bump edits, you will be downvoted to oblivion.
Also, as mentioned in Getting attention for unanswered questions?, consider sharing the question (use the share link, so you can earn badges) on Twitter and other public places - you might attract an answer and a new user.