How do I improve without feedback?

In the never ending search for a permanent teaching position, I am surprised at the lack of feedback I am getting. I had two interviews this month. One was for a part time position in the school I currently sub in. The other was for a full time position in Queens. I was very hopeful about the position in Queens. I was called to do a demo lesson after my interview. I thought it went well. The assistant principal remarked that the class learned more in that one period with me than they have in the past month. A few weeks have passed and I haven't haven't heard anything. Call me old fashioned, but the least they can do is send an email letting me know the outcome. If I didn't get the job that's fine. Just let me know. I will be sending an old fashioned snail mail letter to the A.P. this week thanking her again for her time and to let her know I am still interested in her school. If not for the end of this school year, perhaps in September when they planned on higher enrollment as the school expands. The part time position interview was weird. I was subbing all day and then had to interview afterwards. I felt I did not look my best and I did not get a good vibe from the teachers interviewing me. It was a "group" interview consisting of two English teachers, the principal and the English chairperson. Since the interview I have been called on to sub almost every day. I even had a few interactions with the chairperson last week, but no feedback. The position was to start February 1, so I am assuming either the date was pushed out or they found another candidate. Again, I wish they would just let me know. I have no problem continuing to sub even if I was not chosen for the part time position.It seems bizarre to me that considering the nature of education is about giving continual feedback, yet I am not getting any. I constantly wonder how I can improve. Is it my interviewing skills? Perhaps I am giving poor examples of my work experience. Maybe it's my lack of experience in the classroom? Could it be my age? Like a student, how can a potential or current employee improve if they are not given direction?