Looking expectantly at the glass, mopping perspiration from my brow, licking my lips? A hard, grinning stare directly at the server? Eyes downcast, my hands lying dejectedly in my lap?
A combination of all of the above except for staring at the person serving your drink. I would recommend keeping licking your lips to a minimum unless you are trying to flirt with them.
Another completely valid option is, glance and smile to whoever else is having dinner with you, if you didn’t go alone.
Directly at my groin, please. It’s the best way to show appreciation for my service.
Look into the server’s soul
Look at the glass with thirsty anticipation
Staring at the shaker nodding your head. When they pour, get eye level with the bar and follow the drink level up with your whole head. Make a whistle increasing in pitch as you do this. Pretend to eat the bar like an ear of corn when you get to mouth level. Take the drink in both hands at eye level when leaving the bar. Say “you too” as you depart as if incorrectly responding to “enjoy your drink” even though they didn’t even say that.