Read the NEC sections in Chapter 3 on the different types on wiring methods.  Most all of them contain a uses permitted/not permitted section.
 
Get the mfg applications notes on building wire/cable types/raceways and see what they recommend for their products.
 
Another method I use is to talk to the journeyman electricians.  They may not be able to tell you why certain types were put in, but they generally have a lot of knowledge on what was installed in certain applications.
 
If you have the one-lines and access to the installation, go look at the installation with prints in hand - match then up.  This will give you some ideas of what was okay when this installation was done.
 
You are going to need some help.  That's not a bad, we all started there.
 
carl