I have asked some questions before but I didn't get any (good) answers.
How can I bring it to people's attention again? Can I ask it again?
No, you can't ask it again. It will just be closed as a dupe.
The first rule to remember is that, in general, there is no guarantee you'll get an answer to a question, here or anywhere else in life.
With that in mind, here on SE, you have two courses of action open to you:
Most of the questions which don't get attention or answers here suffer that fate because they're inherently uninteresting.
If you can make your question stand out, make it interesting to research or to answer, you'll have a much better shot of getting the results you're looking for.
One good way to do this is to edit the question to cover the basics yourself. If it's a question about a word or meaning, tell us what you found in a dictionary. If it's about word choice, tell us what you found in a thesaurus. If etymology, tell us what you found in Etymonline, and so on.
If you do the basic legwork yourself, leaving only the interesting part of the question, that will not only lower the barrier to entry (answerers know they don't have to do the tedious general reference lookup themselves), but it will also make the question itself much more likely to be inherently interesting, because what remains will take either expertise or novel research!
Welcome to EL&U, and good luck!
¹ And, like buying an ad, there's no guarantee of results. You pays your money and you takes your chances.
Avoid posting grammar questions at the weekends. The majority of regular users are away from their computers and generally have lives outside EL&U
Create a memorable, or, provocative title, but above all make sure it's descriptive. Titles that say "Is this correct?", "Please help me with this sentence", "which is correct" and "Present Simple vs. Present Continuous" are the kiss of death. For example, the following title: Is “the” needed in the following scenario? tells visitors that the question is about the definite article and nothing else.
Place yourself in the native speaker's shoes. Would you click the question's title, if it was in your mother tongue? Does it sound interesting? Would you want to post an answer if you knew it?
Do your research. See Dan Bron's answer for more details.
Proofread your question, check for typos, missing apostrophes, etc. Avoid text abbreviations such as plz and wanna. The majority of users appreciate querents who care about their questions and spend time writing them out carefully.
EDIT Be your worst critic. Is the question clear? Have you fixed misspellings and typos? Is it focused? Have you shown your research? Speak plainly, include details, but don't go overboard.
Provide a background story. AKA context. Explain why you are asking the question. Did a teacher tell a rule but now you see it being broken? Are you having a discussion with a friend? Do you need this word for your novel? Find a hook, something original to grab people's attention with.
Source? Where did you read this sentence or word? Cite the source, its author and include a link whenever possible.
Study the questions in the HOT NETWORK QUESTIONS. There's a reason why single word requests (SWRs) are so popular. They can be amusing. Original. Thought provoking. They don't require brain work. but beware, they're like novelty toys, today they're hot news but in two days' time, nobody remembers them.
Good SWRs are answerable. Don't set the bar impossibly high, this will only lead to disappointment. Don't demand "a single word" at any cost, be open-minded and flexible, accept also an idiom or a phrase.
Finally, set up a bounty. However, if your question has none of the features listed above, don't be dismayed if it is neglected and gathers dust in EL&U's repository.
One method that has not been mentioned yet is creating a list of bounties with no deadline as a post on meta. Several other sites have done this so far, e.g. Language Learning Stack Exchange. Whereas ordinary bounties may expire before you get a good answer, the bounties in the proposed list would remain valid. Of course, the meta post would need to be a featured question for some time so people find out about it.
This type of list is especially useful for questions that require more research than usual and on sites that (unlike ELU) don't have a lot of traffic.
This is an important question not only because old questions often need better answers, but also because we all need to learn how to ask better questions.
As the earlier answers already suggest, editing a question is likely to raise your chances of getting better responses, but how does it work? I deduced they meant that by improving your question you would attract better answers, which is very true; HOWEVER, it is also true that
simply editing an old question will "bump it" to the top of the active questions list, as I tested and confirmed with one of my own old questions
So this is indeed a shortcut for anybody who wants to 'rekindle' interest in their old questions without making any major changes, but be warned that
you are likely to get a better response only if you actually edit it substantially to make it a much better question!
Note 2: How to write a much better question?
This is explained in the excellent answers provided here by Dan Bron and Mari-lou A.