Hi Annemarie,
Figuring out your target market isn't just about their age and gender. You also need to think about the things that your target customer likes, what kind of person she is, what her "pain points" are, etc. Then you look for those kinds of people on Instagram, and figure out which hashtags they follow (you can do this by looking at the followers of bloggers or big brands your target customer follows). Then, where applicable, use those hashtags for your images.
For example, I know that my target customer likes A Beautiful Mess. So when appropriate, I use some of the same hashtags as the A Beautiful Mess IG account, like #mybeautifulmess, #abmlifeiscolorful (for a colorful IG image), etc.
However, you don't want to pack your image with a bunch of random hashtags just to try and get views. You won't convert views/likes to customers that way. Focus on a few hashtags (I'd suggest 5-6), and use them to target your ideal customers.
Also think about what kind of images your target customer likes to see on Instagram. Does she like to see a few quotes here and there? Maybe some behind-the-scenes photos of you at work making jewelry? Hopefully she likes to see beautifully styled photos of your products.
These are just some ideas to get you started. If you're serious about identifying your target customer and promoting to her, I'd suggest signing up for one of the many e-courses on using Instagram to promote your business. There are also a lot of good blog posts out there with tips for promoting on social media.
Best of luck!
Jessica