For shading, unless you decide to pull from your model, I recommend knowing basic color theory, with knowledge from how this aesthetic looks. These colors normally involve bright saturated colors, but make sure theyre nice enough to look at with your eyes. In the end, it is all preference. In the color ramp, I usually add somewhere between 2-5 different colors to make each one pop and and be distinct from eachother.

Now that youre done with colors, we can move on with some small important things. In the driver, go to the purple guys at the bottom of your shader editor. Right click both of them, and press delete drivers. Now resize them to either 75 or 50. Now you can see the pixels. In the soft light tab, play around with that for each one, clicking "soft light", and choose different options till you find one you like. I normally like using lighten. If something needs to be glowing, you can turn up the emission function.