yes definitely money up front on any commissions (unless it's a friend that you know & see often)... otherwise yeah it's such a potential waste.  I got burned a few times and won't let it happen again.  Of course the art still sells to someone else - but that's definitely not the point.  Anyway - congrats.

I ask for half or all of it upfront, I have gotten jilted a few too many times even after they told me they loved the painting. But no payment, what did they just want,just to see what it would look like if I made them a painting? thats not cool.

That is absolutely the way too do it, I learned the hard way too when I started doing art/craft shows, got stung a couple of times but the product sold at another show later down the road, I actually have a commission sheet they sign, collect 50% down, give them a time I will have completed, contact them and they have 30days too pick up or it becomes my inventory to resell, and there is no refund, with their downpayment and knowing no refund you are guarenteed the sale is locked in.... we all learn the hard way sometimes but it makes us wiser and better business people in the end,,, take care,,, LINDA