G92E0 – Reset the extruder
G1E100F90 – Extrude 100 mm filament at the speed of 90 mm per minute. For 1.75mm filament.

Calibration: Old steps/mm * 100 mm / Length printer extruded = New steps / mm

List of my calibrated filaments for the Micromake D1:

RS-Online PLA Clear – 163 steps/mm – Flow: 90%
RS-Online PLA Black – 150 steps/mm – Flow: 90% – Hotend: 200
RS-Online ABS Clear Red – 170 steps/mm – Flow: 100% – Hotend: 220 – Bed: 100
RS-Online ABS Clear – 175 steps/mm – Flow: 100% – Hotend: 225 – Bed: 100