Have you been to LA before??
You can go to the Chinese theater etc. See the stars on the ground. Hmmm...I am trying to remember what we did in September.
Are you gonna have a car?
Hollywood Walk of Fame is a quick subway hop from Universal, but other suggestions would depend on if you're relying on bus/ metro or if you're gonna have a car.
Also, what time of year? WB tour can be blazing hot (Universal too of course) in July Aug Sept. And June July are notorious for seeing no celebrities at the studios as all the shows are on vacation.