In my line of work as a consumer attorney, I see the tragic results of a lot of different types of scams. One type of scam that I am seeing more of is scams involving tax returns.
A couple of tips -
First, never sign a blank return. That's just dumb. That return can then be used to send your refund to some other person's account or some other similar scam.
Second, never pay someone a percentage of your refund to prepare your tax return. That is also silly and usually means the tax return preparer is less than above board. A legit tax preparer will charge you a flat fee or a set hourly fee.
Lastly, never use any tax preparer that tries to get you to make false or misleading deductions or do anything else that's not totally accurate. Doing so just brings the IRS to your door and where will that tax preparer be? I don't know but neither will you, so you will be on your own. Reminds me of a cartoon I saw one time about a guy visiting his doctor. He asks the doctor to recommend a good laxative. The doctor replies "A letter from the IRS always works for me."
Don't be that guy.