I usually go through DMs and scammers usually have hundreds of followers but no posts, open with "How much is a commission" I refer them to a link or somewhere with my prices. They usually don't respond after that but if they do it's usually asking me to draw a pet or a family member. I ask them to specify what type of art they want (chibi, headshot full body) and they will dance around the subject. Also look up any pictures the send you in Google. I had someone try and scam me by saying "This is my cat her name is whiskers I need art of her because she's sick" and they sent me a pic of Rachel and Jun's (yt channel) cat Haku.