Here's what I thought. I really like simple black wellies, yeah, but I also like them to be a bit more... fun, okay. Why not pimp them up a bit - like someone, I even forgot who or what, suggested in a competition I read about on Facebook, too. Of course I couldn't join in the competition as we Germans are excluded in about half of all the fun, but I still wanted to make my black Hunter wellies look a bit more... individual, eh^^
First of all, you should clean 'em, right! Because no colour will ever stick to fucking dirty wellies full of dried up mudd from the last festival or general shit German weather :)
Then here's what you should have at home (if you're not into arts, an arts student or such things, you might have to look for all that in some artists' specialist or something)
Acryllic-colour base (which is colourless actually, but it's water-resistant once it has dried up)
Colour pigments in the colours you need, logically.
You also need a variety of brushes, something to mix the colours on AND at least a vague idea of what you wanna paint on your wellies.
Then just paint ahead like crazy and hope something decent appears on your boots :) If you're not that daring, you can maybe take some white pencil and draw some outlines on the boot before you use the colour.
Well, that's it... simple and nice, eh? Give it a try :)