Hello! Thank you very much for the compliment! To be honest, the best thing I can recommend for people on Paint 3d to do is to not use it. If you wish to pursue 3d modeling, if you have the ability, use blender. It's difficult, (ive failed to learn it time and time again), but you will have infinitely more wiggle room to create something that's actually accurate to your vision.
For those who cannot learn blender, or those who have devices too low-end to run blender, such cases both apply to myself, the best thing you can do (at least, i think) is to try and treat it like you're drawing. It is extremely difficult to make models that look nice from the front and back, so I personally find it best to work at a singular perspective. You can play around with much more expressive shapes this way, and since you already know where the camera is at, you can easily determine what things are gonna be the focus of the scene, and how you'll decide to fill in empty space.
The lighting in Paint 3d is not good, even if you use the provided shaders they give you. They can be nice as an addition, but I suggest creating your own light source and shadows. I use the spray can, watercolour, and mainly crayon for this. Crayon has the most texture to it, so it's good to use in order to make stuff not seem as flat. I also play around with materials, like polished metal and gloss. Theres no specific process I use, I usually just toy around with different brushes and materials until it looks nice.
The main way I believe my pieces look distinct from other paint 3d models, however, is that I also use other programs to give them better aesthetics. I recommend using any sort of art or photo editing program (i use fire alpaca) to create harsher, smoother lighting in places where you can't do so with the normal Paint 3d brushes, along with harshening background shadows and bringing in brighter areas of light. There is a bug, in which when you select a color from the color wheel, it automatically makes the color pale. You should always have an image (or a sticker, as Paint 3d calls it) put onto the canvas to colorpick from, as doing so like that does not dull the color you're using. Even doing this, though, Paint 3d has a bad habit of having everything look just kind of grey and lifeless, so I recommend in whatever other program you have to use filters to add brighter shades to the piece.
It really just takes a lot of trial and effort to learn how to make things not look shitty. Paint 3d is simply not meant for making elaborate scenes, and you have to fumble the hell out of it to make something that looks good. It's not the worst engine in the world, you can make pretty stuff in it, it's just far from the best. Also, avoid resizing or deleting a bunch of stuff at the same time. Maybe it's just my bad laptop, but I find myself constantly crashing when I do that.
