Doing something as simple as observing the traffic at a bar and ordering appropriately will not only speed up the process time of getting a drink in your hand, but it will greatly enhance your overall bar experience.
First and foremost, before you approach the bar, know your party's entire drink order. When the bartender looks at you and let's you know that it's your turn to place an order, have the drink order complete and your money ready. Don't look back at your friends to see what they want or else I will move on to the next customer who is ready to place their complete order.
Once you place your drink order with the bartender, don't add to it. This will only slow your bartender down. The more you slow us down, the longer it takes for us to get you a drink.
If you see that the bar is busy, another way to enhance your drink service is to order appropriately. At busy times, it's always best to order drinks where the name states all of the drink's ingredients such as vodka/soda, rum and coke, gin and tonic, tequila/sour, Redbull/vodka, etc. Busy times are not appropriate for lemon drops or mojitos. If I have to muddle or serve something up in a cocktail glass, it's going to take me that much longer to get your drinks to you. At times like these, bartenders also appreciate serving bottled beer and shots (not chilled of course). The faster we can serve your drinks, the faster you get them and the more money we make. It's a win-win situation all around.
When a bar isn't so busy, all bets are off. These are the times when it is appropriate to chat up your bartender and ask them for a drink recommendation. This is also when we will take our time and put a lot of pride into serving a labor intensive, muddled cocktail. I actually enjoy making labor intensive, muddled cocktails, but not when I have 100's of people staring at me waiting to be served.
Being a smart customer and gauging the activity level of the bar will only help enhance your bar experience. Please order appropriately.