Vector Portrait Expectations
Here are some tutorials to get you started, they vary in degrees of difficulty so pick a method you think you will be successful in completing.
Vector Stylized Portrait
Monochrome Vector Portrait
Retro Style Portrait
Geometric WPAP Vector Portrait
Low-Poly Portrait
Tools you may want to use to alter your photo first:
Posterizing an image
Levels to add contrast
Levels to add Contrast 2
Keep in mind you should make mistakes along the way... that is normal, just go back a few steps and try again or 'make it work!'
SAVE OFTEN!