I'll assume that anyone interested in this topic already has some understanding of recording techniques so we'll skip the basics...
Instead, I'll give you a few tips on how to achieve different results just by tweaking a few parameters. I can't stress enough the need for creative thinking and importance of inquisitive and experimental approach. Without it, we would have never built this vast pool of different sounds and effects.
Of course we shall not underestimate the importance of having a good studio, quality instruments, experienced musicians and enough beer :), but sometimes we can achieve better results just by employing a little bit of free thinking.
There is no rule on how a guitar should sound, but we all know that feeling when a sound comes out of a speaker, leaving us speechless... and all because we put this filter on, or turned that knob, or moved that microphone down etc.
Within a rich arrangement a guitar should sound fine in most cases. It's only when we take it out of context that we find the need to "beef up" the sound as it becomes the main ingredient of the composition. That of course always happens when you record just guitars and vocals.
Here are some tricks:
For this exercise use two microphones, condenser and dynamic. First one you place around the middle of the neck of a guitar and second close to guitar body. Adjust the microphone according to the desired bass frequency. It's a good idea to use headphones for this so you can hear exactly what has been recorded (avoiding hearing the sound from the guitar body directly). Each microphone is recorded on a separate track and you only adjust bass frequency on a dynamic microphone track. With a rhythm guitar you can record an additional track using the same procedure and then you pan them out as you wish. This method helps you to get rid of equaliser while still retaining a natural guitar sound.
Alternatively you can try a wide spread Mid-side technique.
This time use two condenser microphones. The Mid microphone could be a directional or Omni-directional, and the Side Microphone must be a figure of 8 microphone so it can receive the sound from the sides as well (see the picture bellow).
The set-up is directed towards the 12th fret, but it could be tweaked back and forth with the help of headphones. After the recording has been made, create a copy of a side microphone track, reverse the phase, pan them out, one to the left, the other to the right and then link them together so they always get adjusted as a pair. Now you can adjust the width of the stereo field by increasing or decreasing the volume of each track. You must be careful not to pan out both side microphones to the same position as they will cancel each other and all you’ll hear will be the mid microphone.
To learn about mid-side microphone technique see this video.