-Most expensive is labour.
Any production bakery will rather invest in labour saving devices than in actual human labour. Why? It's just not the actual human labour involved, it's the risks that go with it: The screening process, the training process, the wait time for both processes to kick in, and if they don't, the expenses occured when an ex-employee percieves that s/he is entitled to compensation--or someone jut looking for an easy buck.
-Next comes overhead expenses: Rent, utilities, and insurance. Rent you can't do much about, other than negotiate before signing. You can invest in energy efficient appliances, and design/layout the premises intelligently. Things like energy effecient water boilers, electrical apliances on 220/3ph, remote refrigeration, and utilizing the heat produced from refrigeration.
-Next comes product. You can buy in bulk, saving a bit, but you have to store this, and you sit on your money. Smart operators take advantage of seasonal produce--say, blueberries where they buy in 2-300 lbs in the late summer and freeze, having a years supply, or buying local spuds or onions, and storing them, or growing our own herbs. Smart operators also don't have a menu "carved in stone" they roll and rock with the seasons, avoiding high cost items like, say romaine lettuce in the dead of January, and loading up with seasonal goodies in the summer months.
To sum it all up, it takes an experienced and smart operator to shave nickels and dimes, but anything shaved is money in the bank.  | 
