My general development platform is MS Windows. So one of the general problems I usually face is finding a certain functions information from the Windows API.
First, you need to find the funciton name if you don't already know it. This part is a little tricky as you will have to use the correct keywords to find it.
Now, you either found the function itself (which resides in MSDN) or the function name. If you only have the name then your next step is to find the information. Searching in the MSDN can be painfull, though I've heard of persons that do quite well. I'll show you how to use google to do the search:
google: msdn [function]
This will usually get the coresponding page from MSDN in the top 5 results on the first page. If that doesn't happen it can be due to one of the following reasons:
you misspelled the function name
that is not the correct function name or such function does not exist. in this case, the fuction name is probably an extension from some 3rd party library.