Trusting someone else with money is equivalent to trusting that individual with your life. Based on this, would you really trust your CPA or an investment adviser or a money manager with your life? If not, why would you trust them with your money?
Nothing looks worse in an audit when it turns out your 1099 was lost in the mail and the IRS knows your interest income and it was not included in your returns.
Make sure you maintain a list of all your financial accounts
Validate your 1040 (usually if you have wages), Schedule E (rental) and Schedule C (business).
The IRS website does a pretty decent job of listing how to calculate each line on every form in case you have questions.
Look at every line in the form for deduction and check if you have something for that particular line and if not; you should be asking your CPA about it.
Make sure you take every possible deduction you are legally entitled. Often people are too worried about a potential audit and skip several eligible deductions.