You need three employees to get the most out of it. I've found that one employee will never turn a profit, two can make a weak profit, and three will let you snowball in wealth. You also need to continuously spend more and more on advertising, because it has diminishing returns. It's a good idea to have a lot of money saved up for the first few weeks. There are also profitability and awareness upgrades you can get if you fatten anyone up to blob size and get the whole secret Dizzy's lab feature going, and they're worth sprinting for.