Its simple "knowledge is power" learn as much as you can and understand the beast, no matter what nothing will ever prepare you for the pressure from when you go from mate/apprentice to engineer, it really is sink or swim, i had a freshly trained engineer almost cry the other month because he had a few call-outs in i had to almost console him to stop him crying, 15 year ago when i were in his position i'd of been laughed at and punched for being a complete wet blanket...
You need to be able to handle pressure, be able to think logically if you can do them then you've cracked it ;-) good luck to all wanna be engineers!