Have a go yourself! Here are the steps...
Start with a big circle nose
It's ever so slightly squished!
Next, add some eyes
A couple of tall ovals each side of the nose. Add in some pupils too!
Draw ears either side of his eyes
Basically, draw a C shape with a squiggle in it, then draw it again but mirrored on the other side!
Add a hat
Draw a thin sausage above the eyes for the brim. Then join up the ears with a mushroom shape and add a little semi-circle with an M in it!
Give him some hair
Most of his hair is under the hat, so just draw a couple of scribbles along the ears for side-burns
Draw that classic Mario Moustache
Draw some curved lines either side of the nose, then link the points together with a bunch of Ws!
Finish the head!
Give Mario a bottom to his face by linking the bottom of the ears together with a curved line
Finally, colour him in!
(If you don't have red, you can always keep the hat white and tell everyone he's Fire Mario!)