Finding your market: HOW?

Warning this is not advice!
This is my current quest.

How do I find my target audience, how do I find my base product?

As soon as I *think* I may have found my target audience, and I pursue them, and I make sure that I have appropriate product for them, they are no longer my target audience.
So what happened?
I have some random encounter with a small pod of people who really love my work. They love it so much they actually purchase it. And then they are done with me.
I have very few repeat customers.

So, how do I deal with this, how do I get past this?
I do not want to be a one hit wonder.

Every year I attempt to add something to my line of creations. Based on how sales are, that item either goes bye-bye, or I continue to make them.
Sugar skulls:
I had great success with these for 2 years. Then nothing. No purchases for 3 years. Other than to use up the stock of ceramic bases for larger candle holder skulls, I no longer consider making these.
Dragon bottles:
The first 10 of these I made sold within minutes. Actually they sold out at their first 2 shows. I even earned a few commissions. Now....I have made a total of 3 batches (6 to 10 at a time), I still have more than half of the last batch.

I hit a high note with pirate stuff, then fizzle. (Yes, I know this one was really very much influenced by the Pirate movies, and cannot wait for the next one to be made and released, so I can sell some of this pirate stuff!)

I do not sell earrings. They are amazingly loved when I gift them, but they do not sell. I no longer make earrings, and have even begun taking some apart to incorporate into other projects.

I used to sell via a friend who sells her own stuff in CA. I fully understand she has enough product that she needs to sell just her own stuff. But I did fairly well with her. But again the same thing. One hit wonders. One summer silver mint leaves were a hit. Then she never sold another leaf. Another summer it was silver hamsa pendants. She sold the first 4 I sent her within 2 months. The next 4 she sent back for stock swap out.

I attempt to make a product line. I see if that product line sells. If it does I re-make, and for some reason this is the end stop of sales for that product.

For the most part I really enjoy making one of a kind products. And yes, I know that is completely opposite of this finding the base product line search but I need to have a balance of support items and super sale items.
The support items are to appeal to a slightly larger audience base, resulting in more sales. Bread-and-butter sales. Sales to cover basic expenses.

That is my situation.
So what answerable questions does this generate?