Street events like parades and festivals are a great time to practice shooting. There is energy in the air and people are less guarded. Walking up and taking pictures of strangers is less intimidating than during a regular day.
The beauty of street events is that you are free to do whatever you want with respect to composition. No one is watching. If it works you have a new techniques, if not, who cares.
Practice is really just another word for doing. Doing photography at parades and festivals can sharpen your skills considerably which will be great when you are a hired gun at a wedding or other event.
I always have a good time at parades! Have fun people!!