Please don't count on an upgrade. You don't know how many times I have to come on here and read posts from people who are upset that they were not upgraded! If you really want a kids suite, book it now!!! Otherwise, get ready to be happy about the room you are paying for.
With that said, here are my 2 upgrade tips:
1) The day before you check in, call reservations and see what availability they have for the nights you are staying. If they have a lot of availability, you have a good upgrade chance. If they are sold out for your nights, you might as well not even ask.
2) When you check in, ask if they have a Loews First upgrade available. If the front desk person seems hesitent, try bribing them with a 20. If they said they have no upgrades for that one night, ask if they can upgrade you if you are willing to change rooms the next day.
Hope these tips help.
-Jon