Also, get an air band receiver and listen to it in the car.
1. Your "dummy" calls can appear to fit into a real environment.
2. You can critique other pilots' calls. Note everyone will be the best RT user, but if you can hear what they're doing wrong/not so well, it'll help you to avoid the same errors when you're flying and transmiting for real.
3. It'll further help attune your ear to VHF reception.