It's hard to me to understand sentences like "She likes to be looked at". I know it means "She likes it when somebody looks at her" but the second sentence is natural to me and I can form it on my own while the first I can at best understand but not create by myself.
Especially I'm likely not to use a preposition in the first sentence so "She likes to be looked"
Also, I understand the basic passive voice pretty well:
I will feed your dog -> Your dog will be fed by me.
I was told -> Somebody told me.