That might mean that you create an entire alternate universe with magic, with constant voyages to and from space, but you have to figure out how it is going to make sense in the context of your world. All very possible, but still difficult.
Of course, it may just mean doing research.
Setting a novel in Africa? You may need to research the customs, the setting, the politics, and the formalities. How about a different time period, such as Victorian England? There is a lot of the same you need to find out. Is your character a ninja? If you aren't a ninja (you are, aren't you?!) you'll need to figure out the details that will help make your story plausible to the readers, so that they aren't sitting there going, 'Pfft, what is this they're trying to pass off?'
Of course, a writer doesn't need to fret too much. There are such things as creative license and suspension of disbelief to aid us. Also, making something plausible doesn't mean you have to provide all the facts. It just has to seem real enough. However, I am sure we all find ourselves in the need of some good research. Some might love it, some not so much. Guilty party here! I find it fascinating and exciting, but also frustrating. Sometimes I even find it...disgusting.
Right now, I am working on a novel that is set in the sixties. I managed to acquire a selection of candies from the that period. I thought, What a great form of research! I was wrong. I spat out the first thing I popped in my mouth, and was gargling away the taste. I don't know if I'm brave enough to go on... What did they try to pass off as candy in the sixties?!
In my case, I try to do a fair amount of research before I start writing, but I don't want to worry myself into a corner. The novel needs to be written. I wrote the first draft of a novel recently where my main character is a nurse. I am not a nurse, and so I have no clue of all the medical jargon and emergency procedures that he would know. I would get to a crucial part of my novel where such things are needed and type something along the lines of, And then he did all the medical stuff that he would do in this situation, knowing these things as he does, being a nurse that he is.
I know, I'm talented, right? I can fill in that stuff later when I do the proper research. It isn't the easiest thing to do, however. Google is not always your friend (gasp!) and you have to hunt down books, search obscure websites, and try to see if you know anyone who has any more of a clue (or any clue) of what you are trying to write.
How do you go about doing research for your writing? Do you do it first thing or leave some stuff for later, for fear of putting off your writing indefinitely? Do you worry about whether or not your story is plausible?
Do you enjoy doing research or do you find it tedious?