Connect your guitar into your amplifier using a guitar input cable. Recording your electro-acoustic through an amp is essentially the same as recording an electric guitar, the only issue being that you will lose some of the warm acoustic tone if you use this method.
Experiment with microphone positions. Typically, your microphone should be about 6 inches from the amplifier’s grille, pointing toward the center of the speaker. This will give you a standard sound. Record a test run and see if you like the sound. Moving the microphone closer to the amp will give more definition, and moving it farther away will allow the sound to resonate more before being picked up by the microphone. Generally speaking, to get an “acoustic” sound, the microphone should be a little farther away; 1 or 2 feet from the amp will do the job.
Record your guitar part. If you feel like the notes aren’t clearly defined enough on the recording, move the microphone closer to the amp.
Set your microphone up about 6 inches away from your guitar. If you’re using one microphone, it’s best to have it pointing toward the hole in the body of the guitar. This allows the microphone to pick up the best mix of sound from your guitar. The low-end notes resonate more toward the bridge, and the high-end notes are clearer around the neck.
Record a test and move the microphone as desired. Again, closer provides more definition and further away gives a more ambient, resonated sound. The hollow body will provide warmth and resonance anyway, so it shouldn’t be necessary to have the microphone very far away.
Test both low and high notes to make sure both sound out to your liking. If you are fortunate enough to have two microphones, you can get a great sound by pointing one at the bridge and one at the 12th fret. This gives you a high-quality stereo recording, as one microphone picks up mainly high-end sounds, and the other gets the low sounds. This also means you can adjust the volume of the high-end and low-end sounds individually on your mixer/computer. This method is generally seen as the best option for getting an authentic “acoustic” sound.