I played a PC game called "Osmos" (http://osmos-game.com/) like back in 2012 or so. It has all this electronic ambient music as the soundtrack. However, the soundtrack is not created for the game. Rather, the soundtrack is a selection of pre-existing tracks already produced by a few electronic music artists. The link above is one of my favorites. Source: almost 2 years ago

You can physically demonstrate orbit with some fabric stretched over a frame, but I really think video games are going to be your best friend here. Osmos (Free demo, $5 full) is a great starting point that uses simplified gravity in two dimensions. Orbit (Free app, $5 on Steam) is another, similar game to introduce orbit. Once you've graduated to three dimensions, Universe Sandbox ($30, $20 on GOG) will really... Source: almost 2 years ago

Some professional software such as TrueCoach or Trainerize can help to make your clients experience much smoother and make you appear more professional. Some kind of scheduling system such as Calendly can also be very helpful. You should understand how to program effectively for your clients. Shadowing other trainers can be very enlightening too. Source: almost 2 years ago

I've used Google Sheets in the past, but I currently utilize TrueCoach thanks to it's more professional user interface and various other quality of life features. Source: about 2 years ago