Read Publication 17 and Publication 334 in their entirety, and read them with understanding (look up, research, Google anything that you don't understand in those Publications).
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/p17.pdf">https://www.irs.gov/pub/irs-pdf/p17.pdf</a>
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/p334.pdf">https://www.irs.gov/pub/irs-pdf/p334.pdf</a>
However, you just said this is NOT for a tax business, is that correct? Realistically, if this is just for your personal situations, you are MUCH better off to go to a tax professional than to learn everything. Focus on what your business actually does, and hire experts (such as tax professionals) for everything else. THAT is a recipe for a successful business. When you try to do everything for your business (such as learning everything about taxes for your own non-tax business), your business will not be as successful.
If you are trying to start a tax preparation business, after reading (and understanding) Publication 17 and Publication 334, you may consider taking a class to become an Enrolled Agent. That will PACK your head full of information. Another way to learn things is to go on forums such as this, find a question that you DON'T know the answer to, and research the answer via IRS Publications and Google. That is how I learned A LOT of my knowledge.
