This is by no means the only way to record acoustic guitar, but it is a simple, traditional approach.
The traditional way to record acoustic guitar is to use a condenser mic (or mics). You can use non-condenser mics, but acoustic guitar is definitely one of those cases where the better mics and mic preamps you have, the better your results should be. You can use two mics and blend them but you can also use just one (and avoid phasing issues).
With one mic:
Put the mic in a stand at the height the guitar will be when you're gonna be playing. Start by positioning yourself so that the mic is pointing at the fingerboard roughly at the point where the fingerboard meets the body about 12-14 inches away (this is a traditional mic placement area for recording acoustic, but you should think of it as a starting point). Now start playing and listen to the sound of the guitar going through the mic and coming out through your system (i.e. your monitors). Now start moving your guitar slightly in relation to the mic and see how the sound changes as you move more centered over the sound hole, or more up the neck. Also vary the distance between the mic and the guitar. Listen to how it sounds at 12 inches from the mic. Listen to how it sounds at closer and further distances. Listen to what happens if you change the playing angle. Basically you just want to find the spot where it sounds best to your ears. When you find that, record your track from that spot.
If you use two mics, start with on the neck near where the neck meets the body and one near the sound hole.
In the case of this particular two-mic placement, my engineer was able to solo each mic and listen to it through headphones. As I played, he moved the first mic around the guitar and listened to the results until he found the sweet spot on the neck-side position. Then he locked the mic in the stand at that position. Then he did the same thing with the second mic on the body.
I highly recommend this approach for finding the best micing spot(s) for your particular guitar (and gear) if you can get someone to help you. Even if it's your wife or girlfriend! Get in a comfortable playing position, put the headphones on yourself, and have the second person move the mic until you like what you're hearing, then lock the stand in that spot. If you're by yourself, you basically have to reverse-engineer it -- that is, put the mic in a stand, and move yourself to the best position. You can do it, but it's much easier and faster if you can get a second set of hands to help you.
A good article that goes into more depth and more techniques is here:
http://www.uaudio.com/blog/stereo-miking-acoustic-guitar/
The other thing to note is that once you get a sound you like recorded, acoustic guitar generally requires a lot of after-the-fact processing to A, make it fit in a mix without eating up all of your mix's frequency range, and B, to get anything like pro results.
Generally speaking, recorded acoustic guitar takes an enormous amount of frequency in your mix and you typically need to cut a good deal of that frequency to make that track fit in your mix. And you have to do it in the context of the mix. It is very common for an acoustic guitar track that sounds great in the mix to sound terrible if you solo that track. Often because you have to scoop a lot of the boomy lows and low mids out of the track. You may also have to minimize finger slide noise that gets captured in the recording. You do that by setting a narrow band Q in your EQ, boosting it fully, and then sliding that boosted Q all the way up your frequency range until you hit the frequency containing that finger noise. The Q makes it stand out vividly. Then once you've found that, you flip that same narrow Q so that it now cuts rather than boosts. Drop the dbs until the finger noise is gone or at least minimized. Don't cut more than you have to. if -5db removes the noise, don't cut to -10db.
Compression will also help. And acoustic guitar tracks also respond very well to things like aural exciters and subtle choruses.