Conversation works best if you are showing an interest in the person. Ask her about her favourite ...
... subjects, holidays, animals, hobbies, etc, etc.
She may then ask about yours, so have some respones ready ~ then just let the conversation flow.
As The_Zookeeper said, the problem with the cinema is that you can't chat & get to know each other.
Interupting her at work could cause problems, depending on the place, if it is feasible, you could just pop in and ask if you can meet her at break or lunch.
Or maybe you could wait for her to finish her shift and see her after work.
If she agrees, then say that you haven't seen her around, but that you enjoyed going to see that film and would she like to go somewhere else.
Do you have a local ice-rink or bowling alley, perhaps?
Perhaps she would like to play badminton or tennis ~ or watch a game?
