They say to make your requests general rather than specific, and list them in your order of preference (from most important to least), and you'll have a better chance of getting at least some of them.
The reasoning is that the cast members who assign rooms need to know what you want or value. So rather than saying you want a room "like room 5032" because it's near the elevator, say "I'd like a room near the elevator," for example. In the former case, a CM wouldn't know what to give you if room 5032 is already assigned to someone else, whereas in the latter case the CM could try to accomodate you with another room that's close to the elevator.
(I'm not saying you didn't list them that way; I'm just giving the standard advice for these situations.)
Other than that, it's all down to luck.