Simple.
Coffeeshop- tip any silver change from the rounded to nearest 50c amount IF sugar is put into my t/a coffee when requested (maybe more if they remember my name/order). I do NOT appreciate it when they say they're too busy or they point to the sugar pile. I'm paying $3-4 for something which costs them <50c to make, they can put sugar in. And of course when I get to free coffee time, I aim to tip the price of the coffee subject to coins availability in my bag.
Restaurants- tip the higher of 10% of the meal bill or the amount required to round the bill upto the nearest $5. Exception to this is if I'm eating at a small asian shop or something in which case it's typically not expected and I'll just tip any coin change (which is essentially rounded upto nearest $5 unless I paid with coins). Special service (such as checking on my meal or remembering special niceties, or taking a photo of my gf and me) usually yield bigger tips (typically another $5-10 depending on size of meal).
Bars- I don't feel the need to tip anything more than coin change since drinks are quite expensive. That being said this isn't usually needed since I have private bar tabs with the bars I frequent.
EDIT (to add more)
Taxis- round up to nearest $5 (typically paid via card) unless the driver was rude, disgusting, or did something else to annoy me (e.g. talk on his own phone loudly throughout the convo)