Lisaannjam,
That was great advice that you gave.
In addition to cueing to myself in other people's classes, I also would cue while driving in the car. People must have thought I was crazy in the cars next to me, but who cares?
Christine.... there are great videos that you can get to help you start teaching step and will help with building routines. Check out the following link
http://scwfitness.com/indexStore.php to Saracity workout. They have a lot of videos that you can buy that will help immensely.
The one thing that drove me insane a few years ago when I started teaching was that there seemed to be little resources to show you how to actually teach a good class. With a little research, you can find a few.
Lisaannjam's advice to watch Cathe and really look for how she cues is great advice.
Also- watch how Cathe uses a lot of the same moves in every video, but varies them slightly to create a new move altogether.... for example, when she does insoles around the world, she does a little hesitation move on the third one to make it fun - same count, just a little variation.
I have gone to turnstep.com to look for ideas for routines, but I never end up using any of them in whole. I usually just take some of the moves and make them my own. Also- there is Jumpybumpy.com, but I never really found it very helpful.
Music is very important, as others here have mentioned. I would check out Dynamix- I find that they have the best music. Start out at a slow beat (125-128 BPM) to start with. If you start working at a facility that has a pitch level, you can begin to buy music at a higher BPM and adjust accordingly.
A word of advice - ALWAYS MAKE BACKUPS of your music CDs if you can. These discs will get a lot of wear and tear, and you don't want to be stuck with a scratched CD that you can't play during your class.
You are entering a very exciting time in your life

I know I sound like a dork, but the best thing I ever did was become a step and spinning instructor. You will have a great time.... just remember that things are not always easy in the beginning. They may just talk about you behind your back in the locker room... but take heart because the ones who were there in my very first classes where I made a million and one mistakes are now my regulars who never miss my classes....
Have fun, good luck, and any time you guys need advice, or need support, please don't hesitate to PM me.
Stephanie