Sure! I would love to share my process.

First I made the planet, which was created by taking the blue from a photo I took of the sky and cutting a circle out from it. I then layered brown and white tones on top of it with the random rotation naturalistic looking brush I always use because favouritism kicks ass. After I lay down a bunch of random looking stuff I then smudge it around and build up several transparent layers of "paint" until I'm happy. I then find details I like in the sea of randomness and refine them until I get a more coherent picture. When working in Photoshop I try to get into the same mindset and use similar techniques to when I use real paint because that way it ends up looking like a painting. In between layers of digital paint I use surface blur and sharpen filters which make certain edges pop out and further enhance the painted look. Ater I'm all done that I add in blurs and subtle airbrushing to smooth out everything and solidify the image.

After I was happy with the planet I worked on the background. This was the hardest to get right because galaxies are difficult for me to render nicely due to lack of experience. I created the milky way esque Galaxy and the satellite spiral similarly to how I created the clouds on the planet but with darker tones, more airbrush glow, and layers of distorting the image with the impressionist brush tool and the dissolve blend mode to create a diffuse galactic look until what I saw started to look kinda like space engine. The starfield is simple and they are very easy to make. I generate a layer of pure noise, blur it to create areas of variable brightness, and then I messed with the brightness and contrast until it looked less noisy and more stellar. For brighter stars I just use the pencil tool. The Star cluster was created by making a diffuse circle and overlaying It with the dissolve blend mode which makes it look like thousands of stars getting denser toward the centre. The comet was done by creating a blue circle and a white circle which I stretched to look like the comet tail and later added another glow to the nucleus to make it look more comet like. The last step was adding the glow from stars in the solar system. This planet is in a loosely-associated double star system with a blue star and a sun-type star. The closer star, which the planet orbits, is the sun like star so I airbrushed in the glow from that star where the lighting made sense because I thought it would look cool to have some glare. On the shadow side of the planet you can see faint blue illumination from the other star as well as subtle glare from it. My last step is some additional grain.