If you're worried about realistic or at least semi-realistic of your deserts, etc, it might be worthwhile to sketch out the climatological patterns on the world map. There are a number of world-builders here who have done just that over the past year or so, that I've watched. Karro and Korba's maps are the ones that influenced my first one, however.
Karro's world:
http://www.cartographersguild.com/showthread.php?t=2463
Korba's Calen Ndor:
http://www.cartographersguild.com/showthread.php?t=4812
There was also another that popped up recently which generated some amazingly useful discussion on oceanic currents, but I'll have to dig for it, as I don't have it bookmarked.
EDIT: Okay, I went and poked around for a few minutes and actually found two of the other worldbuilding endeavours that have been undertaken recently:
Laime's world:
http://www.cartographersguild.com/showthread.php?t=6539 The discussions here are good for examples of both tectonics and ocean currents.
Gidde's world:
http://www.cartographersguild.com/showthread.php?t=5508 The discussions here are especially good for ocean currents, and the difference between surface currents and the thermohaline system.
Both of these later posts are good for expanding your understanding of the groundwork, but I feel like Karro and Korba offer good examples of converting that groundwork into actual climate/biome zones. Additionally, in my signature my own endeavour on the subject, with which I tried to be thoroughly detailed.
If you've got specific questions, feel free to hit us with them and we'll answer what we can.
-asp