When recording an acoustic guitar you would normally put the microphone right by the sound hole if there were no pickups mounted in the body. The problem is that the sound will be too harsh and dark. It will have way too much bass in it... This is especially true if you have a big sounding acoustic such as a Gibson J200 or similar brand/model. Here is the tip... Put the microphone between the 17th to 20th frets about 2 to 5 inches away. This will give a much more balanced signal. You will hear the difference right away when the track is played back.
Acoustic basses work the same way. If the sound required needs less bass try the same tip.
If the guitar being recorded has either active (powered by battery) or passive (no batteries required) pickups installed then use the above miking technique as well as feeding the sound from the pickups into the board and mix them together. This is the best way to get a really nice strong acoustic sound.