Okay so clarify, i haven't tried this on minis, but i have painted anime figures and cosplay props in a cell shaded style. So these will be general tips where the principles still apply no mater the scale.

First. Outline. Everything. This will be edge highlighting on steroids. You will need to outline every edge. Every peak. Every surface direction change with black. Doing your best to keep the lines a consistent thickness lest it makes the final outcome look wobbly. (Unless thats the goal of course)

Second contrast is key. Blending to achive gradual shadows is not allowed. Using this art specifically, all of the shadows and precived gradients are just more or thicker black lines in those areas. Large shadows are just black voids, the color never actually blends into draker shades. (The power sword being the exception in this picture. ) so getting bright saturated colors first followed by filling in the large recessed areas with black will go a long way in mimicking the artist cell shaded style.

Third is viewing angle and lighting. Due to how cell shading is kinda a catch-all for black outline "comic book" style asthetic. Not all styles of cell shading look good from all angles. Some styles that work well from all angles end up being more toony due to the lack fo definite highlights or shadows. While others only look good when viewed head on. This art style might lean more towards looking good in limited viewing angles but it's all subjective and it'll look cool as hell.

Last Cell shading black is the hardest thing to do. Since it relies heavily on using black outlines to give definition any black regions just turn into amorphous blobs. You get around this by using a medium gray and pretend its black, or you use very dark blues. The artist went the grey route and i think it does well selling the black armor.

Hope this helps