This is also a question I constantly struggle with. My hubby says, I'm being too "westernized" by saying that service oriented groups expect tip (restaurant, delivery, salons).
When we moved here, I did ask a local, re: restaurant and he told me that if you're in a restaurant and you pay by credit card (these establishments most likely already have the service fees anyway), it's not expected of you to tip, but if you pay by cash, you can leave coins as token tips.
Re: salon, I asked a local mom who works in a salon, she said if service was very good, you can choose to tip, but it's not expected, if service was only ok no tip needed.
For food delivery, I tip a round off figure like restaurants since I pay cash. But I don't tip for grocery delivery (can't recall why I was told not to). . . however, sometimes the delivery guys don't seem too happy leaving. . . so maybe tip is expected?
For massage, some places accept tips, and even have tip guidelines, but another salon claim that no tips will be accepted. So depends on where you go I guess.
Taxi - I just hand them the money and whatever change they give me (which the typical practice is rounding off the fare to the nearest dollar) is ok, don't believe they expect more. . . my friend from LA tried to tell the driver to keep the change last month, and he just didn't quite know what to do, so I told her, no additional tipping beyond what they round off.
Don't know if this helps or just added to the confusion!
