A good rule of thumb is $1–$2 per drink for simple orders like beer or wine, or 18–20% of the total tab for cocktails and mixed drinks. If the bartender crafts complex cocktails or provides great conversation and service, tipping on the higher end is appreciated. For large tabs, a percentage-based tip is usually more appropriate.

Both approaches are acceptable. Tipping per drink works well if you're paying as you go, while tipping on the total tab is better when running a tab throughout the evening. If you tip per drink, $1–$2 each is standard; if tipping on the total, 18–20% is the norm.

Yes, tip on bar food the same way you would at a restaurant — typically 15–20% of the food portion of your bill. Your bartender is providing table service when they serve food, so they deserve the same tip rate. Combine food and drink totals and tip on the overall amount for simplicity.