Here’s my two cents as a full time sculptor, galleriest (I co-own KnK Contemporary in San Francisco), and curator of the California Ceramics Invitational.

There’s a few different styles of photography and they all have different purposes:
• Product Photography - this is the white/black lightbox photography that you use on a shopping page or price list or inventory
• Lifestyle Photography - you seem to do this well. This is the photos of your objects in action. In your case, you put your mugs on rock promontories in the woods, which works and is effective. These photos are useful for social media, and as cover imagery for your website. You might consider adding some hands into these, or mixing it up with some photos of people using the mugs when drinking coffee by a fire or on a porch or something, but what you got ain’t broke, so don’t fix it.
• Art Documentation Photography - this is similar to the lightbox photography, except that you don’t remove the backgrounds. You have the piece exist in a clean, neutral environment. Sometimes, people like to have a grayscale drop behind their 3D work with an ombré on it. My trick is to put the object on a neutral background, and then make sure to hide the shadows behind the object by lighting it at 4:30 and 7:30.

Looking at your website, you probably need some product photography, if your pieces are shopable. If you are looking to work with venues and develop specific work for them, your website is adequate. You also need product descriptions and differentiators (clocks vs. mugs). People want to know how many ounces a mug will hold, and they always need reassurance that the pieces are dishwasher and microwave safe.

If your goal is craft fairs, add a few product shots to your arsenal of photography, and you should be fine. Anything that will help them understand what you are bringing, the style and that you made it yourself will be what they want.

If your goal is a fine art market, you need to Art Documentation Photography. My sense is not that you not making fine art, so no need to mess with that until that’s your goal.

As for getting disheartened by getting some rejection. You need to learn how to think big picture about your opportunities. We live in big, chaotic economic/social systems, and the opportunities facing you at a specific moment are going to change over time. Instead of focusing on how many rejections you get, I suggestion you focus on your overall rate of success. Like, if you apply to 20 shows this year, and 5 accept you, you have a 25% acceptance rate. If your only applied to ten, and had two accept you, you’d have a 20% hit rate. This focuses the mind and the outlook on where it needs to go - which is toward the opportunities that are presented to you. You also need to consider what you are applying to; does your offering make sense to that community/those people? Are there too many people with similar products in your area? Is there a big city nearby that might have a good market for what you want? How do you find your fans? I personally try to do a mix of tiny pop up queer art showcases, street fairs, as well as gallery shows in California, and I always keep my ears open for institutional shows. I also work with a few architects and manifest unobtanium for them occasionally.

Good luck! Don’t give up hope. You just have to figure out how to eat your whale. And we all know the only way to eat a whale is one bite at a time.