I have already mentioned about three million times the importance of self education for those who want to work in this business. In fact, self education is the corner-stone of any success (provided that you really want to succeed, of course).
One of the basic things you learn, when make your first steps in oil hydraulics, is hydraulic symbols and the way they are combined in hydraulic diagrams. Right from the start, this gives you an advantage over those, who do not know how to read and interpret hydraulic schematics - not only you become capable of telling when someone is holding a diagram upside down, but you also gain the right, no, no, the obligation, to come up to such person, and correct his embarrassing mistake by snapping the schematic out of his hands and giving it back in the correct position with an expression of profound superiority on your face...
But there is one more useful thing about them diagrams, which can help you learn more effectively.
Learning process is all about memorizing stuff and building skills, however the most valuable information is the one, that is stored in the "active" database of your attic, requiring little effort to be consulted when needed. This is where you unleash the brutal force of hydraulic diagrams. How? Very simple! By making your own diagrams.
Imagine that you are learning about, let's say, the closed center load sensing pump control. You are talking to an engineer and he gives you a nice explanation of how this circuit works and where it is used, and draws you a diagram. As long as the explanation makes sense to you, you already have the knowledge in your head, so all you've got to do now is to hammer it down so that it doesn't vanish. You just wait a little for the information to settle down, a few hours, a day, maybe, and then you sit down, take out a sheet of paper and a pen, and make a diagram of the circuit by yourself.
Two things happen here - you practice your schematics building skills, and you stuff the active memory of your brain with the so important load sensing principles. Creating something and watching someone create something are two very different things, which involve a whole bunch of different memory accessing processes.
Recreating hydraulics schematics from memory is a very productive way to learn, it allows you to memorize new circuit concepts faster and better. It is especially useful when learning different types of variable displacement pump and motor controls. Whenever you come across some new control and look it up in a catalogue, make an effort to recreate its schematics some time later, as if you were explaining its function to somebody else. If you can't remember it, it's OK to look it up, and try to recreate it later. You'll be surprised how many diagrams you'll be able to remember.
Productive troubleshooting of any system is based on two things: understanding of its basic operation and knowing the components. This easy technique will definitely increase your component knowledge and allow you to pull schematics out of your head on the spot, thus further boosting up your professional value.
And yes - one last thing. Remember the guy you snapped the schematics from? He won't be talking to you for at least one month...