you don't really need to.
30 days out for some places ( Emirls) and a couple of weeks out for others.
if you plan to go at christmas time or high holiday time, it would be wise to make one a couple of weeks out prior.
other than that, no advanced ressie really needed.
let me qualify that statement, some homies will make a ressie at the information/booking stand in city walk the morning of desiring to eat at city walk.
for the park, same thing, except in a high season time.
even then, it isn't always necessary unless you are talking about new year's eve type of date.