The best kind of mug to get are cheap ones from the Dollar Store or from Walmart because the glazed used is more inexpensive. Before you start drawing on your mug take some paper towel and alcohol and wipe it down first to remove anything on the surface that could interfere with the sharpie from adhering to the mug.
I wanted to do something simple so I decided to just go with gold polka-dots. To get a perfect circle I held a nickel up to the mug and traced around it with pencil.
I just kept tracing the nickel all the way around the mug trying to make it look as evenly uneven if that even makes any sense.
Next I filled in the circles with my Oil Based Sharpie Paint Pen. I used a medium point one because I had a bigger design. If you are doing a thin design make sure to get a fine point one.
I waited for the paint to dry a little and I did a second coat. Here is how the mug looked after I filled in the circles.
If you have any mistakes or your pen decided to explode paint (like mine did, more than a couple times haha) no worries. Take a q-tip or a paper towel towel and dip it in some alcohol and it will take the paint right off.
You need to let the mug dry completely for 48 hours. After 48 hours it is time to bake your mug.
Place the mug inside your oven and turn it on to 350 degrees. Set your timer for 30 seconds.
When your timer goes off, turn the oven off but don't take it out of the oven. You need to let the mug cool down with the oven to avoid it from cracking of any sort.
When the oven is cooled down it is time to see your masterpiece!
This is how mine turned out.
ENJOY!