At bars, 20%, or a buck or two a beer is perfectly acceptable. Cocktails should be tipped better, tied to how much effort it takes to prepare them. If you're going to be at the same bar for a few drinks, consider tipping generously on the first drink to help you get quicker service on future drinks.
At hotels, leave housekeeping $5-$10 a night, using the pen and pad of paper in the bedside drawer to leave a note indicating that the cash is for them.
10% on rideshares and taxis, $5-$10 on food delivery.
Pretty sure that's a pretty exhaustive list of places it's a significant faux pas to not tip. You'll be prompted to tip at a lot of fast-casual (order at the counter) places, but it's unlikely to be taken an insult if you don't. Anything higher than 10% is exceptional.