In general just voting to re-open, or commenting on the question that other people should open it, will not help. You need to understand the reason it was closed and do something about it.
- Closed as a duplicate, but the duplicate doesn't help you: edit your question to make it clearer what is different in your case. Add a comment saying that you have done so.
- Closed as unclear what you're asking or must demonstrate a minimal understanding: edit your question to include the missing information. This might be showing what you've tried so far, elaborating on what your error message is, or the like
- Closed as offtopic: you might have to just accept this one, but if rewording would make it clear it was on topic, do that
- and so on
Now people who are able to vote to re-open will actually be motivated to do so. If you edit while the question is still on hold (5 or 7 days, I am not sure which) it will automatically be put into a re-open queue. You can read more about the closing process, what on hold means, close reasons, and the re-open process at the help centre for Stack Overflow.
In the rare rare case where a mean and misinformed person closed a perfectly good question that needed no changing, you can post about it on meta. Use the [specific-question] tag and include a link.