Is there a specific timing that I have to wait to vote in a post, be it up/down, to close/reopen, delete/undelete? Should I wait something to vote? Or can I do it immediately?
Voting should be done based on the state of the question/answer when you see it. If you aren't happy with your vote, you have a five minute window to change it. If the post if edited after the grace window, you are again given a chance to undo your vote.
Immediate votes provide feedback to the author of the post. As Cody Gray stated in a previous answer
[Voting] increases the likelihood that the user will take notice and actually fix their question in response to your suggestions. Unless you're dealing with a particularly conscientious user (and this is rare, because their questions are unlikely to be candidates to close in the first place), it's more likely that they'll ignore your comments as long as they can continue to get answers.
[Vote Closing] prevents a flood of immediate answers (arguably a symptom of the well-known "Fastest Gun in the West" problem) that are speculative at best and/or will be completely invalidated after the question is modified to turn it into a real question. Those answers don't do anyone any good, and they're best avoided if at all possible.
Upvote/Downvote should be cast as soon as you read the post. Good? Upvote. Bad? Downvote.
Voting to close depends on the close reason.
- Duplicate should be instant.
- Off topic due to belonging to other site should be instant.
- Off topic due to requesting tool/library should be instant.
- Other close reasons (e.g. unclear what you ask, too broad) should not be instant in my opinion, better leave a comment first asking for details or asking to improve quality, and only after a while vote to close, if the OP can't be bothered.
Voting to delete should be instant only in extreme cases of obvious crap, otherwise better let the auto cleanup process do its job, leaving others a chance to improve the post until then.