I know it sucks to hear, but it's all about practice. It'll click one day.
It can still be tricky and I definitely find myself resorting to direct vision here and there. Eventually I will have the experience to not have to do that anymore, but honestly, do what you can to get out of dental school in 4 years. You'll have plenty of time afterward to perfect your skills.
So basically start developing good habits but don't feel like you HAVE to do indirect vision just because it's better for your back, neck, etc. If you need to do a good prep/restoration for a competency or something and direct vision would help, use direct vision.