If you want a low-noise pre-amp you'll find many op-amps are noisy and you might need to chose carefully. This will matter most for a microphone preamp rather than guitar though.
With audio preamps you first need to know your source's output level and impedance and look for a circuit that is designed for that. Feeding a guitar signal to a microphone preamp for example might lead to over loading and distortion, and vice-versa might mean insufficient output or too much noise.
The generic class-A amp is pretty simple and can perform quite well - you'll need to find a tutorial that explains how to set the gain and input impedance and choosing the right bias point.