Beauty and art play an integral role in gardening regardless of the garden's purpose. Even in the most pragmatic of settings beauty is still necessary; pollinators are naturally attracted to consistently flowering gardens. Bees will even create associative routines to help remember where the nice flowers are thus helping your cucumbers, apple trees, or pumpkin plants to produce more fruit. Perhaps more importantly, focusing on beauty for most people will help to make the garden more inviting and enjoyable in addition to more productive.
Beauty, as in art, is subjective. It is subject to the individual and cannot be prescriptive, however, there are some general guidelines that you can follow in order to assist you in your decisions. Take special care to think of shape, form, colors, and texture. These are all formal elements of art and their interplay will help to define your garden. For example, if you have a garden space with squared edges, allow bushes and shrubs to be more flowing and whimsical. If you like your plants and trees to be more structured try using an irregular shaped edge. Vary the color of flower blooms as well as leaf color in a color palate with two or three colors. For inspiration I follow Monty Don on various media platforms.
This complementary strategy can be done on any scale and usually with little to no expense. Simply start by incorporating your strategy into normal pruning and trimming. With a little planning you can start to improve whatever space you have. Ultimately a garden is a place where you should go to be happy. Whatever that looks like to you, a place that brings you joy is the priority.
For our newly finished gardens we are trying to add structure that gives way to the wild. The irregular shape of the beds and layering of textures, colors, and forms will be a nice transition to the vegetable gardens we are planning. These will be deliberate spaces that will hopefully be measured and as uniform as possible. But given that we live in the woods, it is important to us to be in concert with our surroundings and to appreciate them as much as possible which will in turn help us to enjoy it all even more.