A couple months ago, I switched from a hybrid bike with regular pedals to a road bike with clipless pedals all at the same time and I too was petrified of all the changes! What I did first was go on a couple completely flat trail rides where I wouldn't have too many distractions. This gives you time to get used to the shifting and the initial instability of a road bike. You can also practice clipping in and out without much consequence.

Then, practice stopping real quick on a flat surface and pulling your foot out (remember twist out, don't pull up!). If you're able to adjust your pedals I know you can make it easier or harder to clip out, but my pedals don't do that (you'll of course want to do that on a trainer). After that it was hilly rides I was most afraid of, so my husband suggested I go up slight inclines and practice clipping out. He also explained though, that with clipless pedals you're more able to just power up a hill than with regular pedals, so don't give up, just push through.

It also helps to anticipate hills and stops, by shifting down when you see a hill coming, and clipping out prior to stops. The first couple hilly rides I did I shifted down lower than I thought I would need, just to be safe, but as time goes on you get an idea of what you can or can't handle. One thing you want to remember is that when you get a little more tired, you may clip out with one foot, but lean to the opposite side, because you're shaky or just forget. I had an "oh ****" moment where I did this but I quickly threw my weight to the right side and I was good. There will be these moments, and there's that panic, but you can usually save yourself. I haven't fallen yet. *knock on wood*

Good luck. It gets easier and more fun with time and practice. The sooner you start, the sooner you can get over your fear, and realize that it was no big deal and enjoy your ride!

-Jessica