I could recommend the books by Forrest Mims, and websites like All About Circuits, but I bet you already saw the thread a couple of weeks ago when I recommended that before.
Here's another way to look at a circuit (this example is DC):
Start at the +V supply, whatever it is, and then look for the ground, wherever that is. Some circuits don't draw the trace all the way back to the negative battery terminal, so anywhere you see the three horizontal lines, you have to take that as ground. For each path you can find from the + to the - imagine a current flowing. On any given path, there could be a bunch of components, and these will decide how much current can flow through that path. If a path has lots of resistance, or something like a capacitor in line, then there probably isn't much current flowing on that path. There are probably many paths. You could follow all of them, but before giving yourself a headache, look for the ones that use the most current, meaning, the least resistance. That gives you an idea how much power the whole thing needs. Next, follow the power to some of the devices, like relays, IC's, motors, etc. Often these get power all the time, but some of these get switched on/off by other things on the circuit. Noticing that, you can tell how one thing controls another thing.
Yeah, hard to know where to start, but if you start by looking at a little piece, figuring that out, then looking at how the next pieces attached to it work, you can start to draw the big picture.