i painted my boots this year. i used plastic friendly sparay paint. i didnt really try so hard but if you want them to look good you should sand down whatever you are painting so it is a ruff surface for the paint to stick to. you could do a primer or something but i didnt do that. and your gonna want a lot of coats. also depends where your painting but as you know boots flexx...paint doesnt. you will probably notice that eventually the paint will crack. so youll probably want to retouch the boots with paint every once and awhile. montana spraypaint is really good.
also people die theyre boots with rit dye i think
i saw a kid that just used colored sharpie on his old salomons, you could do that if the boots are white, it actually looks pretty sick and stays on well