Almost Scammed - How to Spot an Email Art Scam

Yes, I almost fell into the trap.  They sent me an email with the title "I want to purchase your artwork", so of course I had that moment of happiness (and feeling of being accepted!)  and clicked the email.  It read,

"I would like to make an immediate purchase of your artworks. Also let me know if you accept credit card as method of payment."

I replied and asked which pieces would he/she be looking at.  The person then expressed interest in 2 pieces from my instagram account, to which I reply with all the details including price, payment and complimentary shipping (assuming the person is based in Singapore).  The total cost of the artwork is SG$220.

It then gets really weird, because the person responds with a longer email stating,

"I am interested in the pieces and I'm ready for immediate purchase and my private mover will pickup the piece from your location once the payment is made. I would like you to make additional custom purchase link of $405.00 which my private mover charges for the pickup, shipping of the piece and also moving of our other personal effects to our beach house where we are celebrating our wedding anniversary. All you have to do is to deduct the due amount for the piece and remit the
additional shipping fees to my shipping agent through PayPal in order for them to schedule the pickup from your location. Kindly get back to me as soon as possible so I can make the payment today.

Thank You."

Well, the person was polite, but the thing that stuck out like a sore thumb is "All you have to do is to deduct the due amount for the piece and remit the additional shipping fees to my shipping agent through PayPal in order for them to schedule the pickup from your location. "

Why would I pay $185 to ship my own artwork to a potential buyer? Initially, I thought it was some sort of mistake, but then when I started typing my response, my instincts kicked in and I immediately thought, "It's a SCAM!".  I quickly googled and lo and behold, yes, it was a scam. I didn't even bother to reply.

What Should  You Look Out For?

a) They want you to send money to them for shipping (or other things)
b) It's an immediate purchase
c) They don't tell you in the first instance which pieces they would like to purchase. This is what happened in my case - they just sent an email saying that they would like to purchase my art and that was it. Nor did they say that they were textile art lovers or art lovers in general.
d) When they did send me the images of pieces they were intending to buy, they had chosen close up shots of the creations.  That should have set my alarm bells ringing in the first instance!

What other tips do you have on how to spot an art scam?