I've been riding for 5-6 years now and skating for longer, and I tried the same thing about 2 years into it. I found that the switch took a while to get used to, but once I had the muscle memory I could switch flawlessly. What I did, as silly as it sounds, was look in a mirror while standing on my board and looked at my stance. I analyzed the key points in my stance, such as the angle of my feet and legs etc, and essentially replicated this with the opposite legs. I went from goofie to regular, but the same technique should apply to the opposite.
As for practice, I did a couple things:
I didn't go cold turkey on my original stance. I made it a gradual switch, riding on each near the end of my runs so as not to injure myself and give myself a chance to think about it
As dumb as it sounds, I put my boots on and strapped into my bindings and just switched back and forth, flipping the board around on each hop to get my legs into the rhythm.
I took my skateboard and found a short, gradual hill and just rode that up and down, switching my footing for each run whenever I had free time to also help with my muscle memory.
I eventually got it down pat, but it took me about 4-6 months. Don't be discouraged if you don't get it immediately. Keep on riding and enjoy the season!