Any INFO HELPS!!!!!

Okay so I am due September 21st with my 2nd baby I am REALLY REALLY wanting a vbac. I had my daughter March of 2015. I was I labor for 12 hours and only dilated to 4cm at the time I was 16 years old.. at the 12 hour mark my doctor came in and asked me if I wanted him to give me a c section or if I wanted to keep trying for vaginal I did not want other random people looking down there so I had him do a c section... I am really wanting a vbac. My experience with my first was just horrible I could go into more detail but the doctor and the hospital was just an awful experience... so what are some tips to help me a have a successful vbac please help!!!! 😩