Great list!These are some of my top porteño tricks ( I used to stop at 3-4 cafes on a daily basis a long time ago when worked in corporate sales )
1- To order small coffee, look at the distant waiter and mimic with your thumb and index finger a small cup, he will bring it and will be happy he saved the walk.
2- If in a hurry, sit order coffee and check at the same time and pay. Enjoy coffee at your own pace. Then only you decide when to leave.
3- Go in, sit, make coffee sign, drink it, leave enough cash to pay for it + tip, get up and when they look at you point at your cup and money. Proceed to go.
4- It seems to me like they hate to come and go, especially if watching soccer or chatting with some other waiters, so use as much sign language as you can. Especially to order your check, do the sign gesture just so they bring it.
5- If for some reason everything fails, and you are desperate order at the cashier, pay, do not tip and cara de orto. Never return.
Enjoy.
PS: These tips and hints are mostly valid in the city of Bs As and in or around downtown and normal neighborhoods, not super touristy. Waitresses would not understand most of these either.
PS2: Congratulations! You are very very close to acting like a true porteño
I always pay immediately when getting coffee.
The best places to sit aren't always the best places for service. A nice corner or over by the window can be the nicest places to talk to someone and enjoy your meal, but they're often the worst for getting service. If I know I'm not going to want to sit around all day, I sit in the middle in full view, or where the waiters pick up the food to deliver to the tables.
I never sit outside on the sidewalk anymore, especially these days. Apart from the fact that sometimes the waiters never come outside, sometimes you get interrupted 20 times by people trying to sell things or ask for money, or the couple next to you start smoking just as your meal arrives, and you choke on the exhaust fumes of the passing cars.