I'm trying to create a world map for my fantasy novel. My problem is that I love designing things, and I'm finding myself bogged down with figuring out how desert A got where it is, and how plain B's temperature is different than plain C, and so on. I've never studied that type of thing in any great detail, so my knowledge of how the different ecosystems form is limited.
This has led me to ask the following question: how can I know if a map is realistic?
For the majority of readers, knowing that plain G would be cool instead of hot, or that a forest would require more rainfall than is mentioned, is not going to be a problem. However, there will invariably be the one person who knows how all those things work, and if the impossibility of the map really gets to him, it could sour his reading experience. That's not something I want.
So how do I know if a world map is realistic, short of knowing how every ecosystem on earth forms? Is there a cheat sheet?
Post-Answer Note: While I've marked the answer by John, it's not the one that helped me. It does answer the question, but what I ended up using was the resource linked by Monica in the comment below. It was detailed but still simple enough to provide exactly what I needed. I was able to create a realistic world in a matter of hours, and have zero doubts about whether or not it is realistic.