Hello Sally,
The main thing to consider is that no taxes are withheld from royalties payments. That means, unlike when you get a paycheck from an employer, no one is withholding & submitting the income taxes to the IRS for you; it is your responsibility to do that, and if the royalties are significant enough, you are required by the IRS to pay them quarterly. The easiest thing to do is start by setting aside at least half of all your royalties payments for taxes (do not spend it all!). Unfortunately, there are too many additional steps to detail here; the IRS is not an agency that you want to cross, so my advice is to hire a good accountant to make sure you report your taxes accurately & timely.
Good Luck,
Andrew
