Quoting Daniel Hauck
This may seem like a trivial question, but would you mind describing in detail how you go about painting lego pieces? What brand/type of paint? Any tips or tricks? As time allows, I want to build one like yours and wouldn't mind getting the painting done in advance.
Using spray paint needs a bit of practise to get a good a result. Use satin finish paint so you get a finish like Lego. Put on a couple of thin coats of paint and let it dry well between each coat.