One thing that's pretty clear from the reports we get here is that the method of making your requests really doesn't have much bearing on whether or not you get them. Whether you call, fax, write a physical letter, or use online check-in, the request is getting typed in a field on your reservation record. How the data gets into the field isn't important.
The factors that really do affect whether or not you get your requests are often beyond your control. Things like how many rooms there are that meet your criteria, and how many people are checking out of rooms that meet your criteria on your arrival date.
There are some ways to improve your odds. Keep your request list short, clear and simple, with your most important request listed first. For instance, "upper floor, pool view." Or, "first floor, close to transportation." Or, "connecting rooms, building 3." Don't try to help the room assigner by looking up a series of room numbers that have the view, floor, building, etc, you want. The odds of a specific room being open on your check-in date are never good, and then the room assigner won't have any idea why you wanted that room. It's better to describe your ideal room than specify it.
And always remember, room assignments are not set in stone. If you'd prefer a different location than the one you're assigned, you can always speak with a CM at the front desk and see if they can find something that better suits your preferences.
