I apologize but I'm one of those Americans that can't stop tipping. Although my tipping is limited to taxi drivers and the hotel staff since I always stay in the same hotel with extended stays, I spend close to 6 months of the year usually about a month at a time. The hotel staff, bellboys and house cleaning, are always happy to receive tips. In addition to tipping I also try to get to know them personally and not treat them like "the help". In the morning, I take a taxi to my office and the drivers are pretty regular so I add a few yuan all the time. If I stay close to New Year, I like to give red packets out also. I've never tried to tip in a restaurant nor would I think its appropriate.
For me, building that relationship does matter and the staff is always ready to help me out when I need, like coming quickly if I call for something, bring extra water, towels, etc. I am not advocating an attempt to export tipping culture, it's just my experience. It's kind of baked into me and I only do it where mentioned above. I've never had a tip refused in China.