The way you make money in this tycoon is by pressing the Green Flag. Make the most money by pressing the Green Flag when the flag is in the center of the screen. Press "Stop" to open the Stop Shop. Turbo mode (Shift+click on the Green Flag) can also be used to burn off the extra speed.
I saw a game once where the game's level wasn't reset with the green flag, so you could stop the game and come back to it without losing progress, so long as the page wasn't refreshed. So, I made a game based on that concept.
