I shared with her something I did some time ago that has helped tremendously, and I have forgotten to put it on my website here (but will do so right after this posting).
What I created was a contract form, which gives the buyers a space to describe detailed needs and desires for a commissioned piece. It helps clients figure out what they really want in design, subject matter, color scheme, size, and price point. These are important considerations. Instead of just saying, "Can you make me something really big with a New Orleans theme?" they can be sure what they're asking for is something they'll love to have in their home.
What it also does is let clients know that this is my business and I am serious about the painting requested, that I want to create the best match for their space as well as their budget. (I price my art by size) The contract ensures that they get the painting they want on time, and in return, they stick to my payment schedule.
I think the form takes a lot of pressure off both parties because there is no obligation on either part until the contract is complete. It leaves me free to paint other things and them free to spend their money on whatever they consider a priority. But once everyone involved agrees to the deal, there should be a smooth, seamless transaction that makes everyone happy. Of course, you can always buy "off the rack," as it were, from my gallery of already-painted paintings.
Although I'm not fond of other artists copying my artwork, I don't mind sharing this form with them. Cheers!