The IRS offers courses on filing taxes every year.
Called 'VITA' and 'TCE'
In these courses you volunteer to help others to do their taxes for free. You spend a week in a classroom taught by an IRS auditor or sometimes a team of auditors.
It also gives you a wonderful look at the internal workings of the IRS. Auditors are divided into sub-specialties, and commonly do not know anything about the other sub-specialties. So even during the class, when fielding questions they are often calling the 1-800- help desk to get referred to the right sub-specialty desk.
My wife and I have each attended VITA courses for eight different years [volunteering to help others file their taxes each time].
These courses go over each form and it's effects on your over-all tax stance. They show examples of ways that H&R Block commonly messes up folks taxes. and I have seen 'professional' tax assistants attending VITA classes, saying that they learn far more about taxes directly from the IRS in a VITA class, then they could ever learn from the courses that private companies offer.
This practical knowledge has allowed us to itemize our taxes; and maintain a zero AGI or often a negative AGI many years.
If anyone is not itemizing their taxes, I do recommend that you consider attending a VITA course near you.
We would find paying taxes would be a huge chunk out of our income, if we actually had to pay such.
Naturally I don't qualify, having ditched the landline four or five years ago! 
