Here are some tips.
Computer Scoring – … Tax returns are “scored” using two systems – Discriminant Function System (DIF) and Unreported Income DIF (UIDIF). The Discriminant Information Function System (DIF) score gives the IRS an indication of the potential for change in tax due, based on past IRS experience. The Unreported Income DIF (UIDIF), as you can imagine, scores the return on the potential for unreported income. The higher the score, for either, the more likely the return will be reviewed.
Apparently these tips come from the IRS itself! When would it make sense for the IRS to teach us how to avoid an audit? It would make sense if the ways of cheating on your taxes were known and easy to describe. Then the IRS just announces it will audit anyone who does something that looks like that. But if there are always innovative ways to cheat on your taxes then an announcement like this, if truthful, probably only helps cheaters avoid audits.
On the other hand the IRS’s objective might be to maximize prosecutions. Then they want to lie about their audit policy and hope you believe them.