You want bartenders to like you? Of course you do. Why annoy the people who work hard to create your favorite libation of the moment? This good article in the New York Times gives you some tips about what to do, and perhaps more importantly, what not to do. Many thanks to my friend Chuck for posting a link to this article.
Here's my summary -- be nice, be patient, and know what you want to order. If the place isn't busy, put down your phone and have a real live conversation with your bartender. Trust me, you'll be fine. It's not about how much you spend (but you should tip generously). Let me give you an example ..... Ms. Wulf Cocktail Den and I have been patrons at our favorite watering hole for more than 15 years. Compared to other patrons, we spend far less but we always get great service. Why? Because we speak with, not at, our bartenders (and we tip generously).
Be a good person and your bartenders will love you. My liver can vouch for it.