As every musician has his own idea of what a great sounding guitar means, there is no "optimum miking technique“. It's far more important to know how different factors in the recording and miking process can affect the final timbre, so that you can find what you are personally looking for. Especially when working with only one Mikme, much can be achieved by carefully positioning the microphone.
Find the sweet spot
Different parts of the guitar will radiate different frequencies and in different directions. Especially if you're close‑miking you can focus on various aspects of the instruments just by the chosen microphone position. Basically, you can use the Mikme like a natural EQ by changing its position and direction to the guitar.
A good starting point could be to place the Mikme approximately 20cm in front of the guitar, aiming at the 12th fret, where you can usually achieve a fairly good balance of the body resonances and liveliness from the strings.
Positioned towards the neck, the sound becomes thinner and brighter, pointing at the sound-hole you can focus on the deeper, more bassier parts. Moving the Mikme towards the guitar it will sound more direct (be aware of unwanted string sounds, if the MIkme is positioned very closely).
If you move your Mikme back a little, a more unified sound of the whole instrument will be picked up by the microphone (but also more of the rooms reflection).
Move, move, move
The precise angle of the mic and distance from the guitar will vary according to the guitar, the track and the desired sound. By tweaking the exact position and angle of the Mikme you can play around to get the sound you like.
In this video you can see a few examples of standard mic positions and you can listen to the effect this different positions have on the sound of the instrument.
Have fun playing around with the sound of your guitar.
One more thing: Please make sure to have the gain of your Mikme set-up properly before you start recording. Learn here how to perform a soundcheck with your Mikme