/ic/ - Artwork/Critique

I need some advice, how to improve. So I'm on this local trading group and i started trading my shitty custom pet portraits for consumables and stuff, so far it worked pretty well, did around six pet portraits (framed) and got exactly what i wanted.

The last two didn't work out though, for one I was suppose to get laundry detergent and a plant (which they offered) and the last one I already received (a train ticket of 25$ worth which i used) but she never offered to pick it up or replied.

So I'm just really wondering what I'm doing wrong and feel bummed. I feel like the ones before were even worse? And maybe it's just flaky people twice in a row, but i don't know, I need an outsider opinion on this, maybe I have my head stuck in my ass