Originally Posted by
keeton
Full service hotels will usually pre-block the upgrade the afternoon before your day of arrival. You can check your reservation details on marriott.com to see if they have done so or not.
If not, I have had the best luck calling the hotel mid-day the day of arrival and speaking with the front desk (not GM). I let them know I'll be arriving that evening and if any upgraded rooms are available. They can block you in then.
I rarely have any luck getting a suite when requesting upgrades by email, though sometimes they will pre-assign a nicer room. And it is almost impossible for me (and many others) to call mid-day as I am usually in the air.
However I do find I get better rooms by asking directly at checkin. Still no suites (like SPG and Hyatt) but usually something better than average.