I often recommend a balancing exercise to help with this - it certainly helped me, and now I can navigate the trickiest of switchbacks. It really is all about the balance.
On a grassy area, get on your bike, clip in and just practice doing a track stand for as long as you can. Often, you will need to move the front wheel, or re-shift your body weight to maintain your balance, but the trick is not to pedal, or put your foot down. How does this help?
Think about making a tight turn - you need balance, and typically, you are doing this at slow speed. I have one switchback on my local trails where I can literally stop, and steer my way around the turn using my balance.
It's also a good skill in other areas!
Good luck - sounds like you are doing really well!
SheFly