I grew up/live in a rural area without public transportation, so I have no personal experience to draw from. I've traveled to Europe a few times and by trial and error, was able to figure out the metro/train, etc., but have struggled with buses. My few attempts at (local) bus travel have been frustrating. At best, I'm on the right bus, but not never know how long it will take to get there, or where to get off, as things were not "announced" or "labeled". I invariably miss my stop, and waste precious time. There must be a trick to it, and I'd love to know how to read/use the bus schedules that are provided.
I have found that the key is to get a printed bus schedule, which are reasonably reliable. You can almost always get these at the TI. Arrival/departure from main city stations are usually pretty close to on time, even in Italy, in my experience :), but at little intermediate stops buses may tend to vary from their scheduled arrival departure times more than trains do. Just keep your eyes open and ask the driver or a local sitting near you to let you know when you arrive at X. I have done this many times and always gotten good help. BTW, this is a good way to open a conversation for a pleasant drive.
I'm a born-and-bred Chicagoan, having taken public transportation for many years and I have more than a bit of confusion when it comes to buses in other cities, so don't feel bad. For starters, most bus stations have an information booth or kiosk where there is somebody who can help. The challenge is to find it! Bus drivers come in 3 flavors: helpful, indifferent, and surly. Even if the driver doesn't speak English, if you have your stop written down and show it to the driver, the first 2 types will help you get off at your stop. For the 3rd type, as Marjorie mentioned, your best alternative is to ask some other people on the bus. FYI, some newer buses do have an internal LED display hanging from the ceiling, announcing the next stop. Also, in some cities, the bus stop signs in the street have the name of the stop on them. They can be a bit of a challenge to spot from within the bus, but it can be done.
If you are traveling in Germany, the German Rail website, www.bahn.de will show you regional bus connections, particularly if you select "local transport only" or if there is no rail connection to that town. Then it is easy to print out the entire schedule for that bus (towns, times) and you can follow it as you ride and see when to get off.
In metro areas, the local Verkehrsverbund will usually have a website and give you travel information between stations, points of interest, even addresses.