For Doing This Exercise, Just Make Random Shapes & Lines in Your Sketchbook. It Will Help Your Linework Become More Fluid.
Centering is a Part of Eye Training, This Involves Drawing of a Line & Judging its Center. After That, The Marked Point is Checked Using Divider.
Step 1 - Draw Two Lines a Smaller & Bigger One, Then Put a Butter Paper on it & Trace The Bigger Line
Step 2 - Now Keep The Butter Paper Somewhere Else & Immitate The Smaller Line
Practice Drawing Object by Simplifying it Into Simple Shapes
The Most Easiest Exercise. Practice Making Two Dots at Different Distance & Connect it Using Lines Without Any Tool