That's why I hire an accountant! Even so, it takes a *lot* for me to gather all the documents needed for the accountant to do the return.
Gradually I'm getting better. Used to turn everything in the week before the deadline. This year I was a month early. Maybe next year.......
If you are sure of getting a refund, you can file for an extension -- very easy, just one page. Even if you owe, you can file for an extension as long as you send in money to cover what you owe. This gives you an extra 3 months to get your act together for filling out the return. However, I do *not* recommend this! It just means it will be hanging over your head that much longer.