To write on a porcelain mug, you need a porcelain pen with a brush tip. You can use it to write in different styles; see what works best for you. Start by cleaning the mug thoroughly (then do not touch the surface to be decorated, as your fingers will leave grease marks). After that, you can get started. If you are not satisfied, wash the mug and start over; it's as easy as that. When you are satisfied with the mug, let the paint dry for 4 hours, then harden it for 90 minutes in an oven at 160°C. Dishwasher safe at 55-60 degrees max.