What is the best way to organize a classroom to benefit students with autism spectrum disorder?

I am moving into a new classroom and new job description next year. I will be teaching four students with autism spectrum disorder in a mobile unit. I am aware that the classroom needs to be structured with defined space for each activity, but haven’t seen any concrete examples. Can anyone give me some good ideas or examples? Thanks!
Wow! I’ve gotten such great responses already. I should add that this classroom will have two assistants (a total of three staff members). Students are ages 14 to 20.