Hey there. I'd start out with music videos. I tried riding a Clydesdale when my skill was still set for a pony. I did a story video back in the day. Spent days editing (so much work and hardest part in my opinion) and got only 40 views. Might be opposite for you so try what ever you're passionate about!
I build movie sets on The Sims 4, not The Sims 3. I can give you a few pointers when building an acting stage for different scenes and what lighting to use, etc.