You can use ordinary paint colours. Anyway it worked with me.
Dunno what you mean exactly. I once painted my ranger boots, which are made of waxed leather, colour rubbed off over time, but i asked a shoemaker what he thinks about it and he told me to wash down the wax first using acetone, paint it and use "Simplicol" (a shoepaste that contains wax) to wax it again. Always planned to do a second try using this method. Additionally i'd use pre-cut removable adhesive foil and spray paint. But that's only the way, i'd do it and i'm not really experienced.
Look up jacob patterson on youtube, he has a whole channel dedicated to painting shoes and some very good tutorials as well
if your painting leather just sand it with rough grit sand paper and and then get it damp and paint it with acrylic paint... this works on canvas shoes aswell though ive had better luck with leather
I have used vinyl dye spray paint on leather many times before dying shoes. It is primarily used for automotive, re-dying carpet and upholstery. It comes in a variety of colors from most automotive supply stores and some hardware stores, but specialty colors can be ordered from automotive supply shops. It is not recommended for leather in automotive applications because it does not work as well with the after treatments associated with it, IE "Armour-all". The other choice isn't so much paint but, a dye that comes in a ton of colors, it allows you to paint on the dye, then when dry you buff off the excess. I have used this on leather armor where I want detail and vibrancy. Fiebings Leather Dye is the brand name, but their are others
Go to any corner on Mexico and you will find some one that will do it for a dollar, they are called boleros =]
I saw an article in a biker magazine about painting a leather seat with Krylon. They took 111 (an industrial solvent like dry cleaning fluid) and repeatedly wiped it down/let it dry until the leather was very dry and dull. Then it was sprayed with very light coats of paint until it reached the desired color. The paint supposedly soaked into the leather. I havent tried it yet myself. I think it may be called perclorethylene also.