I did a quick sketch portrait drawing with step by step .The final result will be vector.Wacom Bamboo A5 tablet was also used, however you can achieve the same results with a mouse or sensitive brush.
Step 1: Start With Eye
Getting to the creation of eyes. Take the Pen Tool (P) and create a path that reproduces the outlines of the eyes and the shape of the shadow around it
Step 2: Eye
Creation of eyes is the most important work, because we see human eyes every day.
Step 3: Nose
Now create the nose, using the Pen Tool (P) and brushes
Step 7: Finally Result
Finally result adding some effects with using Photoshop tools