Say I have a question and I'm not sure what Stack Exchange site to ask it on. Is there a place to ask a question and get it routed to the correct Stack Exchange site?
First, you need to do some homework. So, having your question in mind, you could think of a few keywords to search for. You can search for your question in the network broad search page on StackExchange.com.
If not found, check the site list if there are some sites that could fit. Then read the
help center > Asking page to see if your question is on-topic there.
If you are still not happy or in doubt, and need some advice, you can ask your question here, as Martijn told you in his answer.
Asking about where to post your question is on-topic here.
Tell us as much detail about your question as you can and tag your post with site-recommendation and we'll tell you a) if the question would be suitable for the Stack Exchange model and b) on what sites it could be on topic.