How do you actually tip in USA?

If you sit at the bar or go to the bar for your drinks you should tip the barman each time. I worked in a bar in Manhattan and the barmen always hated tourists who wouldn't tip per drink but only at the end, sometimes they would even point that to the person! The barman will be more inclined to buy you a drink back if you tip this way.

Working as a waitress my weekly wage was ridiculously small, if I remember correctly it was $120 but I made alot in tips! Same goes for chambermaids etc.

You don't always have to tip in cash either, I was often tipped by credit card, the person would add my tip on to the credit card and then the barman would put it through at the end of the night! Sounds dodge but was commonplace.

Most people also tip taxi drivers.

A waitress I met told me that where she worked the floor staff had to tip the bar staff when they came on shift. The bar staff had little direct contact with customers so wouldn’t get much in tips from that source. If the floor staff didn’t tip the bar staff, the bar staff would not serve them, gave them bad service etc. So each member of the floor staff started the evening out of pocket and was relying on tips to cover what they had paid the bar staff and then for their own benefit. Something to consider when tipping.

I was in a restaurant in Phoenix last year and the service in my opninon was awful. Now I tipped $1 just to make the point (bill was about $75 pretax between 3 of us).

I was virtually ambushed by the staff insisting I leave a proper tip. I refused to due to the service and ended up complaining to the manager due to this treatment who in fairness apologised on behalf of her staff and assured me that it would be dealt with.

I think that it is a pretty poor system where you are expected to tip and are harassed otherwise. It should be to the discretion of the person. Now don't get me wrong, I tip well where I think it is due (up to 20% if I think the service was outstanding) but I absolutely refuse to tip if it is below par.