Mini-Mazzer here, and a 20 year old Livia 90.
I find the most important things are:
1) fresh beans, preferably 3 to 7 days after roast
2) clean equipment.
3) good water. I buy the water from a vending machine nearby: 5 gal UV purified, reverse osmosis, filtered, etc.
4) proper grind
Lot's...