I recently submitted an article and after I sent it, realized I had failed to check whether a magazine was still in print. Checked it out and, sure enough, they had gone out of print several months ago. This was a classic example of a blonde moment (err- a dumb moment, anyway) that does no good for anybody. I've done this a few times throughout my 3+ years of freelancing and it's always embarrassing, though editors are very kind about it.
How can you save yourself from this?
Check and cite even the most well-known facts. Check to make sure pi is 3.14. That the world is round. That Columbus sailed it in 1492. That the ocean is blue. Worst case scenario, you lose fifteen minutes to confirming your own knowledge. Best case, you save yourself a lot of time and trouble.
Do the whole read-aloud thing. I'm much more of a fan of reading aloud short pieces because I don't get laryngitis as a result. Reading aloud can help you catch silly errors that otherwise your tired eyes glaze over.
Make a checklist of submission guidelines. Sometimes bloopers come in the form of forgetting to include your address, or formatting, or something that's a forgettable quick-fix. When you find magazine guidelines, make a brief Word checklist of how to submit the article so you don't get rejected on a stupid little thing like email attachments.
Any other tips for preventing silly preventable mistakes? Dying your hair brown might work, but then again, I've had auburn hair for my whole life.