When you finish your work, and post it.... let your customer know...?
A few times recently ive only noticed an artist finished a commission once i saw it in submissions, the artist didn't send a shout, or a note, or anything.

I don't always check every single submission that comes in to my inbox... heck, i won't always be watching every artist that i commission from.
Do let your customer know you've finished the work, please.

Thank you.