Be at least 30 minutes late to your scheduled visit with the Owner.
Act like a load calc is a waste of your time.
Act like you know everything and the Owner knows nothing about HVAC.
Include unnecessary extras in your proposal that the Owner really doesn't need.
Suggest that other firms that sell & install the same product line may be on the verge of going out of business, leaving the Owner high & dry for warranty work. Refuse to name names. Scare the Owner.
Suggest that anyone submitting a lower bid than yours, for the same job and same equipment, will do inherently inferior work.