8. Some bartenders drink during their shift, but not all of them
Some bars don't allow it. Some bartenders don't care about that rule. It's not uncommon for a bartender to do a few shots during a shift to take the edge off and as hospitality lubrication. But many have a general policy of not drinking with customers, and will go so far as to pour water in their own shot glass instead of vodka to maintain the illusion that they are fun party dudes.
9. Bartenders don't always remember a name, but they always remember a tip
Tipping well is the number one way to get a bartender on your side, but an experienced barkeep can usually tell when you're trying to buy their friendship. That won't fly. Also, a good tip isn't always just cash; it can be a good attitude, a bit of well-timed banter, or just the ability to read the wavelength of the bartender and act accordingly.
10. A bartender's "favorite drink to make" is what you'll most enjoy
Ordering a bartender's signature cocktail might earn you a slight nod of approval, but usually your barkeep is much happier to make you something you're not going to regret spending eight bucks on. If you're looking for drink advice, give a few hints as to what you enjoy or ask what the bartender would be drinking if they were on the other side of the bar. Odds are they are also professional drinkers.