>>but i see some of designers are doing vector using photoshop... its like masking them using pen tool.. then using a paint bucket to change colors etc etc
using a pen tool to draw lines and a paint bucket to fill them in is not 'using vector' ... photoshop does not use vector for anything but the way it handles text before rendering. It is a pixel based program ...
it sounds like what you are referring to is paths ... if you are trying to trace over an image to turn it into a cartoon, the only way to attempt it is using the path tool to place points along the outline and dragging them to create the curves. The less points the smoother the lines will be ...
then you use the paths menu to 'create selection' or 'stroke path' ...
its a lot to explain in a few steps though & I suspect this was more an attempt at sig views than a genuine question.