>>6510949you start by downloading GIMP. :^)
for chromatic aberration you can either move one color channel to one direction and another channel to another direction or you could use motion blur in different directions per channel, for video effect there is a filter. for dithering you can change the color mode to indexed and select a type of dithering you like.
make a decent color palette with pink, light green and purple, it's always handy, save all templates you can find and make them look as flat as you can.
