I need to be hurry up :)
I cover my cups with a towel on the preheating pad to get cup more hot than usual. If it not an illustration part of art like somebody portrait or mona lisa :)) you will done in 2 minutes.
If you will check some of my early posts in one of them I was show temperature of the drink :) 59C in the end of my latte art.

Anyway you need to plan what you want to draw before start it. And organize your process.