If you were to ask me the best tip for going to Disney's Hollywood Studios or even Walt Disney World as a whole that most guests don't take advantage of, it's by far not asking enough.
What do I mean? Well, there's a lot of opportunities out there to have better park experiences that many guests never take advantage of becuase they simply don't ask a Cast Member. Many guests I think feel awkward, intimidated, embarassed or too modest to ask a Cast Member something that might be fun. Let me explain how the power of asking a Cast Member can result in something you might not have gotten before.
So you're riding the Tower of Terror during a particularly slow time, usually park opening or perhaps close to park closing and you notice that while you're getting ready to be assigned an elevator there's maybe one other family or two around and no one else. You think to yourself, "How cool would it be if I rode in the Tower of Terror alone?". I've had this situation pop up and I asked the Cast Member something along the lines of, "Is it possible for me to ride by myself since there's really no one else here?". I'm fairly certain my request has been honored every single time.
How about on the Great Movie Ride where many times I hear from other guests who would love to get the cowboy hijacking scene instead of the gangster scene. All you have to do is ask the Cast Member near the load area if you can ride with the cowboy hijacker and they'll be more than happy to accomodate you. Granted, you may have to wait a little longer, but they often will help you out.
When I'm dining at Hollywood Studios restaurants I'll find the menu changed from the last time I was there, but that won't stop me from asking my server if something I had on the menu once is still available. Or if something from the dinner menu is available for lunch. Or if there's a special that isn't on the menu but usually available like the tasting plate from 50's Prime Time Cafe. If I didn't ask, I would never be able to take advantage of it.
At the Backlot Tour, I love to grab some friends and volunteer for the water tank scene. Best way to get picked is to ask. Just ask the Cast Member at the entrance about volunteering. They are usually all too eager to take you so they don't have to ask other guests if they're interested.
I think you're seeing by now that by asking a Cast Member, there's often a good chance they can help you or point you in the right direction. As long as your question is a fair one, most of the time I've found Cast Members very willing to help and really the worst thing that will happen is they will say no. If that happens, smile, say thank you and move along. There are no guarantees with anything I've outlined, but if you didn't ask, then more than likely none of these opportunities will be available to you.
On your next visit to Hollywood Studios, if there's something that you think might be possible, do not hesitate to ask the Cast Member. Be sure to ask in a curteous and happy tone and you'll be amazed by the results you can get!