Firstly, get a good guitar – that means one that sounds good acoustically, which rules out many purpose-built electro-acoustic guitars. Secondly, change the strings and play them in. Thirdly, be a great guitar player.
When all that is in place, it's time to look at recording technique.
Notice the word 'clean' in the title. If you're recording at home the one thing that is going to make your recording less than clean is reverberation. You can't get away from it in the home – the rooms are too small and the reflective surfaces too close.
Recording engineers fear small spaces. They always sound bad, and making a recording in a small space is a game of making things good and continually trying to cover up problems.
So there are two approaches to working around the problem of a small space. The first is to try and make the walls go away. Surround your sound source and microphone with as much absorbent material as you can. Clothes, bedding and even mattresses are good. There is no such thing as overkill here as if you under-do the absorption, you will end up with high and mid-frequency absorption, but the low frequency reflections will still get through. It could sound worse than before.
The other approach is to work with your surroundings. If you take your guitar and microphone around the house or apartment, you will find some places sound better than others. Perhaps you will find the magical sweet spot where your guitar sounds really great.
Microphone technique in itself is less relevant than 'experts' often suggest. Use a decent mike, avoid the direct sound from the sound hole, don't get too far away. And experiment with the mic position.
But you will get a vastly different sound if you record the guitar in stereo. This can make an immense difference. Suddenly the problems go away and the 'wow' appears.
You can position two microphones together in space, pointing to the two ends of the guitar. This will localize the sound in the stereo image. Or space the mics apart – this will give the sound almost of two guitars – one in one speaker and one in the other.
Lastly, don't panic if your acoustic guitar recording doesn't sound perfect. Listen to commercial CDs – you will often find that the acoustic guitar sound is wanting. But in the context of the whole mix, this often doesn't matter as long as the song comes across effectively.