More visitors
Hold [Left Shift] + [Left Ctrl] + [Left Alt]. An airplane, bus, or boat with more visitors will arrive.
When you are in Dinoland, just ignore or delete the message about the cheap gate price to get a lot of visitors.
Island select
Hold [Shift] and type allparklands at the island selection screen.
Money
Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor to edit the "standard.sam" file in the "/data/levels" folder inside the game folder. Scroll down until the "Bank balance stuff" heading appears. Go down a few lines and change the starting balance from "$50000" to any amount.
All rides
Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor and open "rides" file in the "data/levels" folder. You can copy the rides from one level to another. Choose a level and copy the rides from all the other levels into it. Note: This works for rides and side shows.
Easy money
These best way to use this glitch is to go to a puzzle sideshow that has a low play cost. While somebody is playing, up the play cost to $10,000. Make sure that you hit the confirm check to get that price activated. When they finish the puzzle you will get the $10,000 instead of the lower play cost they started playing at. Nobody will play it at $10,000, so lower the price back down to a fair price. You can do this as often as needed. Puzzle sideshow works best because it gives you time to raise the price while the customer is playing.