Just a different way to phrase anna v's answer
The Standard Model can be imagined as a model formed by combining certain quantum field theories and fine - tuning to match experiments.
The keywords are "to match experiments". This means that the Standard Model agrees with experiments (to a large degree, anyway). Therefore, it is an accepted theory that describes our universe, along with a certain sort of model based on General Relativity.
String Theory, on the other hand, is not completely experimentally verified. Unlike the man - made (i.e. fine - tuned and all that) Standard Model, String Theory is a natural theory, made by building on fundamental postulates, and hoping that it wiill match experiments. If it doesn't, it will just be plain mathematics, not physics.
And if it does, it is Physics.
SO, if you want to get the physical insight, or in other words, if you want to study string theory in a physicist's point - of - view, as opposed to a mathematicians's, you'll need to study the standard model first.
This post imported from StackExchange Physics at 2014-03-12 15:55 (UCT), posted by SE-user Dimensio1n0