My apologies if someone else may have asked this question. But, as I couldn't find it via search I'll call this a "super-meta question" :-)
I try to avoid asking duplicate questions. (Hopefully, most others are doing that, but, perhaps, not.) Sometimes, when I type my question, the search will display a matching (or similar) list. However, in most cases, it doesn't. When I search for a question separately (i.e. using the search box), it becomes very difficult to find a good match.
I assume that this is not as much a problem with our site but a general fault of Stack Exchange.
Can you offer some guidelines on how users can improve their searches on this site? Is there a way to search by both tag and some "keywords" combined? That may help a lot.