The No. 1 way people mess up their taxes, according to an accountant

It's tax season. It might not be as charming as engagement season - or as worrisome as divorce season - but it's a crucial and unavoidable part of the year.

However, if you're not meticulous, you could be losing money that's rightfully yours - or forcing your long-awaited tax return to be delayed.

John McCarthy, a certified public accountant and president of McCarthy Tax Preparation, which provides tax preparation and bookkeeping services to people and small businesses, commonly sees clients mess up their taxes through a small, but avoidable, mistake.

"The number one mistake that I see is proofreading errors," McCarthy told Business Insider. "The IRS verifies your tax return against information they receive from employers, banks, and the Social Security Administration. It pays to spend a few extra minutes proofreading and comparing your tax documents to your return."

Aim to file your taxes well before April 15, so you have time to go over everything with a fine-toothed comb, from ensuring you didn't neglect an important form to double checking all your arithmetic.

Here's a helpful guide for troubleshooting common proofreading errors that befall hastily done taxes.

And if thoroughly proofreading all of your paperwork sounds tedious, just remember McCarthy's wise words: "Nothing holds up your tax refund faster than an incorrect Social Security number."