You can start a Showtime at any time in the game by pressing
together. However, to achieve this you have to choose well where you are going to start to get it on the first try and these tips can help you get there:
On the map screen switch to Road Rules to see how many streets you'll have to beat. The goal is for all the streets to turn from red (or silver) to gold.
Start with the busiest streets as this is where you can score faster. When you start Showtime your goal is to cause as much damage as possible, so smash everything: cars, trucks, traffic signs...
Buses are your best friends because each one gives you a multiplier, so as soon as you see one hit it. And if you manage to hit ten in one go is another achievement, but generally 5 are more than enough.
Every time you press
it's a spin, but if you press it several times the car flies through the air so it's better not to press it too much or you can go over the cars without damaging them.
When your energy bar is empty Showtime ends and your points are added to the multipliers, and also the distance traveled, so try to go as far as possible to get a higher score.
Every time you get a Showtime Road Rule the game lets you know with a message. If nothing appears, you haven't beaten it and you must try again. Also check the color of the street on the map to be sure.
And finally the most important tip: you can start a Showtime at the end of a street with little traffic and continue towards busier streets without a problem to get the necessary points to win. Good luck.