What you want to check is why the viewer doesn't think your answer is a good one. Most likely they think there's a problem with the structure of your answer. Make sure your answer is a clear one, and isn't anecdotalAnecdotal. An good answer should read like a (good) essay, starting with a clear thesis, supported by a strong argument, and concluding with a decision.
Now we could leave it at that, but by itself it's just a statement, a One-LineOne-Line answer. We want to avoid that, so let's take a look at what comes next: The supporting argument. This is where we want to convince anyone reading our answer that we're correct. Why should the viewer take your side? Here are some suggestions of methods you can use that can make your answer great, and convince others that you're correct:
Sources are always great. Giving someone a source instantly gives them a sense that you are telling the truth, and it lets the people reading your answer learn more about the subject and (hopefully) reach the same conclusion you have.
Just make sure that when you use sources, that you're not relying on them for your argument to work, Otherwise you'll just have a Book of LinksBook of Links. Your argument should stand on it's own without the sources. The sources are just there to make it stronger.
Statistics! People love numbers, and they love charts and graphs even more! Using relevant statistics can be very informative for the viewer. However,these can be tricky to use as they're easily faked. If you are using a statistic or a graph in your argument you will need a source for where your numbers are coming from, otherwise you risk turning your viewers away even if they're correct! Likewise, overusing statistics can drown out an argument, making it UnclearUnclear.
Give both sides. If you can tell the viewer, in a short summary, what the argument against yours is. You can then provide a counter-argument against it, preventing any possible comments in the future questioning why your answer is the correct one. Not only that, but providing views from both sides instantly gives a sense of trustworthiness, especially if everyone else is only talking from one side of an argument.
Use examples. Even if you haven't experienced the exact same problem, if you have any related experience, you can use it to make your argument stronger. It shows that you are talking from experience and not conjecture.
I think this answer could be improved. See: Why is my answer
being Down-Voted or
Ignored?