You have a few good answers already, but let me add a little twist...
I like people using documentation and it is a great sign for your professionalism.
Not using documentation
I know enough programmers that stumble along without a real plan for long spans of time, trying this and that by chance, picking through old source code where whatever they want to achieve seems to have been done already (but hasn't quite) and so on. Frankly, I detest this kind of approach. They never get very far, often have to ask people, seldom take advice and prefer to continue like this forever, seemingly.
People frequently googling for tutorials or code snippets including SO, without ever referring to documentation, irk me to no end. This behaviour is a huge trap, in my opinion. It leads to a kind of programming fueled by half-baked, arbitrary, unsystematic "knowledge". Those programmers tend to end up with a lot of prejudices. This is where nuggets like "never use
git rebase", "never use
not in in SQL", "always do XXX", "never do YYY" come from. They will find it very hard to think out of the box, come up with new ideas, form intuition about how to structure their applications and all that stuff that makes up great developers.
I would urge you to solve any problem first by looking at the documentation/reference, and then look for SO or other snippets.
Of course, there are exceptions. If your problem is quite obviously something like a bug, or something very, very, very special which is unlikely to be handled in any sort of documentation (e.g., a special combination of libraries/modules etc.), then by all means go straight to SO.
If it is something that could easily be figured out by documentation/API, then I would suggest sitting down and working on that particular part of your programming language / libraries etc. so your knowledge gets tighter.
The best kind, for me, is a programmer who, when encountering a new topic, takes the time to really sit down, dig into it, get a good overview and good technical understanding. This is most times achieved (again, in my experience, with the many programing languages I had contact with) by reading the good old documentation including API references and so on. This can, in my opinion, never be replaced by anything else.
I do not find it outlandish to read, for example, the old C++ classics (good old paper), the Gang of Four Design Patterns, the (online version of the) "Programming Ruby" manual, the extremely well done Perl manpages, the Git book, certain RFCs, the HTML/XML/etc. specifications and so on from front to back. I would do and have done that even in my spare time and would, frankly, expect it from any programmer worth his/her salt (depending on what they are working with, obviously). I am also thoroughly aware that I am (at least in the companies I worked in, in the past decades) quite alone with this opinion.
(N.B.: Obviously you do not need to memorize huge lists of API references, but at least gloss over them to see what's available and what the "spirit" of the API seems to be.)
After being thoroughly comfortable with the topic, then is the time to look at 3rd party code for inspiration, or to look at older SO questions (or ask new questions yourself).
You might also find that when you have absorbed one field like this, it gets very easy to find answers by zooming right into the meat of wherever you get your documentation from (man pages etc.). At this point, the autocompletion of your editor might also just be enough already. And you might as well pretty soon know when something is just not possible with the tool you are working with, saving a lot of futile searching.