Yes, It is possible to crack not Only NEET but any competitive exams without coaching and In fact half of the students are Not From the coaching and Even many students without coaching secure Good ranks, If You follow Proper Timetable and are well aware of syllabus and work on concepts and Problem solving then You Can easily crack NEET it is not a big deal , People are cracking UPSC without Coaching , By Appearing without coaching will bring the raw intellectual rather than those who are Just spoon feeded so Just get focused You can crack it.