How to avoid air bubbles while pipetting?
You're still pipetting too fast, you should move the piston slowly and evenly to avoid air bubbles. Also make sure that you wait a second or two for the liquid to rise before moving the tip out of the liquid reservoir. 

Pipettes can also behave rather weird with any liquid that differs significantly in any physical property from water, e.g. very viscous solutions. 

You can find a few more tips in this document from Eppendorf or this one from Thermo Scientific.