Yup agree with the others about getting a good farrier out. My mare used to trip all the time. As I learned more about hooves (as I got odler) I realized that her toe has be consistently too long throughout her life. When I started trimming she stopped tripping. I'm not perfect by any means but her toe is shorter than it was.
Of course, now she hurt herself and can't bend her leg enough so she's back to tripping occaisionally now.