Bus stops in Rome are easy to find, with big often electronic boards next to them displaying bus numbers and the approximate arrival time. Nice way to know if you have time for a quick espresso before your bus is due to arrive at the stop.
Buy your tickets beforehand. They are the same tickets that can be used on the metro and trams, and you can buy them at bars, tobacconists or machines at the stations.
A single ticket costs 1€. If you’re planning on making multiple journeys then save money by buying a day ticket 4€, a 3 day-ticket 11€, or a week pass for 16€.