I took the time just now to go through and draw out most of the common plant deficiencies in pictoral form. This diagram is by no means an exhaustive reference for all deficiencies and certain plants vary in their symptoms, but in general most deficiencies will look something like the diagram below.
There is a red dotted line that shows deficiencies that show up in new growth and deficiencies that show up in older growth, this is an important line and attention should be paid to it!!
Hope this helps people identify what they have a bit better.
