Most important step when customizing your shoes.
It kinda sucks, is tedious, and boring, but crucial to making durable custom sneakers.
Here are the steps i do in prepping each pair i work on.
1. take shoe laces out
2. extra stuff the shoe (pack it tight, gives you a stronger surface to work against along with popping them creases up)
3. grab your acetone or nail polish remover (its like $2, and needed, without it your paint cracking, peeling, and chipping off)
4. in the areas you want to apply paint to, rub down with a cotton swamp or corner of a towel with acetone. dip your towel or cotton ball into the acetone, and apply, put a little bit of elbow grease in it. really make sure to cover the area and rub. What the acetone does is remove the factory finish on the shoes. So that your paint is going directly to a leather/fabric.
5. reapply acetone
6. tape jail, i splatter mostly now so tape is obviously crucial in my work, even when i was doing regular sneaker customs and restorations though i used tape. tape off edges neatly so you can get neat edges. if you are comfortable with a brush, go for it and let the edges guide you with no tape! YOLO!
7. one thing i do that most people lack on is this prep step. Although you used the acetone to remove the factory finish, and angelus paints are flexible and made for leathers, i have found that it still doesnt wear to the lengths i like. Or i like to produce and sell. Before i touch a shoe now with paint, my last prep step is to hit the area with a small dab of spray adhesive. if you want to paint on rubber, you need to do this. the spray adhesive builds a insanely stronger grip for the paint to the material. yes it is a bit sticky and will ruin a brush or too, but that paint will stick on there 100x better. i promise you. after you apply the paint (Step 2) this is where step 3 of sealing it comes to importance too. as the shoes will obviously be sticky and catch dirt & dust if not sealed.