Tutorials / Lessons for Reading Electrical Prints and Control Wiring Diagrams

I'm a mechanical engineer, if something is broken my first method of solution is to hit it with a hammer.  If that doesn't work, get a bigger hammer   But I would like to have a better understanding on how to read and understand wiring diagrams especially related to controls and relaying.

Are there any good lessons or lectures online that you'd recommend?

Kidding aside, I do understand the basic concepts of relays and controls, but I struggle with interpreting the normally closed / normally open contacts of a relay regardless of whether the relay itself is normally energized.  Watching some one step through it or explain it a different way could be very beneficial for me.  If what I said was complete gibberish, start me off of the dummies courses!

Youtube is your friend with lots of videos on this topic. 

Also, there is a ton of information on this website http://electrical-engineering-portal.com/ just search for what you need. Great source for application guides too!