That if you don't pay it, you go to jail.
My father was fond of saying you need
three things in life. A good doctor, a
forgiving priest, and a clever
accountant. The first two, I've never
had much use for them. But the third -
(he raises his glass to recognize
-- Oscar Schindler in the movie
That's a very big question. Here are some tips.
First, new companies often owe a minimum amount of tax depending on which state they are in even if they do not make any money. For example, in California, that amount is $800 per year. This can be a lot for a new company who is just starting out.
Next, depending on which state you are in, the type of entity you choose, such as C Corporation, S Corporation, or LLC will have an impact on how your taxes are paid and how much tax you will pay.
Lastly, if you are an officer of a company, you'll need to pay payroll taxes which have to be paid quarterly to the IRS, so an accountant may be necessary depending on the size of your company.
Get a good accountant. Learning as you go is not advisable.