Here’s my pro tip. Take it how you will. We always bring $100 in singles on every cruise. Most times, when walking up to the bar, I will tip the bartender 1-2$. The bartenders start to recognize this/you. Then, when the bar is busy, they’ll see you in line and know what you’re looking for. Many times they’ll make my drink and point to me in line. I’ll politely say excuse me to other passengers and make my way up to get my drink(s). I’ve found killing them with kindness (even when you may not want to) goes a long way as well.
Same said for the buffet area or pool deck. Tip for drinks and those servers will always walk by and make sure you’re taken care of.