Are you riding +14 and +12 OR +14 and -12? Clarifying this would help. If you're riding +/+ it would help to set your rear binding to either 0 or anywhere between 0 and -15.
A "negative" on your back foot would mean your back foot is pointing away from your opposite foot. Doing this first will help your setup to be more switch-friendly.
As for actually riding switch, practice, practice, practice. Force yourself to do it. Set goals. (I.e. I'll ride this green circle trail entirely switch).
I find that when I coach my athletes (who are younger), all have a tendency to ride in the backseat, meaning they lean back onto their back foot to try and control their board, which is wrong. Your weight should be on your front foot 100% of the time.
Can you give us more info on what you're doing wrong? What it feels like? I'm sure Snowolf will chime in eventually...but any more info would help.