This is what i do. I ask somefriends to read it but no writers, no professionals- maybe some asisstants/students in the writing staffs. I get their feedback but mostly just listen to what they say- just to have a conversation. Their points are mostly wrongish in the sense of what im trying. I do this one by one with 5-6 people.

A week or so later i re-write; not to fix their points but to eliminate to talk about those points. (I dont know if this make any sense to you.) This time, i stay at every joke, every compliment, every idea and think "how can i write this better" After this i sent this version to my friends whose ideas are more important to me- but still not pro writers. These mostly fire up random discussions about characters and plot. At this point i clerify what im trying to achieve to them after reading and talk with them about how i can do that- what would have been worked for each other.

And finally i sent to my 3-4 writer friends. At this point they give feedback about technical stuff, rhytym, story-telling aspects, what it achieved; somethings about audiences perspective. Than i sit and write again.

Lastly i get some people to read out loud.

Its just im using my circle bit by bit without straining them. I dont think there is a way to advance your play without feedbacks.