Righto... First things first, good choice of microphone there. The 4040 is lovely for acoustic guitar.
Okay with acoustic guitar you really want to aim to do as little post processing as possible. Some EQ, reverb and compression will likely be needed but ideally if you get a good sound going in then you shouldn't need anything too drastic.
As for mic placement and dampening, well it depends on your room and more specifically, what you are recording. Is the acoustic going to be used in a mix along with other instruments or is it going to be the primary instrument. ie. just guitar and vocals etc.
Regardless, here are some general guidelines.
1. Start by setting up a kind of 'ghetto' sound booth. Drape some blankets or something similar over a couple of boom stands and build yourself a little den. The idea here is to minimise the sound reflections being picked up by the mic. At the very least have something behind the mic.
2. Place the mic around the 12th fret of the guitar and about 8-12 inches away to get a good starting point. Angle the mic towards the soundhole. You don't want it directly over the soundhole or you will be getting excess air pressure in there which could cause some unwanted boominess.
3. This is tough to do on your own but try to monitor the sound, perhaps through headphones. Move the mic around until you find the sweet spot. This takes experience so don't expect to get it spot on the first time you try. Mic placement is one of the biggest factors when it comes to recording acoustic guitar, it really can totally make or break the sound.
4. In general if you want a more intimate sound you go closer to the guitar, and for a more general 'strumming in a mix' type sound go a little further away and allow more of the room to be captured. Likewise if you are doing soft fingerpicking type stuff you will probably find that a closer placement is better.
5. Once you have recorded it the first thing I would do is insert a nice EQ in there. Roll off some of the bottom end. A low cut anywhere from about 60hz-100hz should do it. If it is going to be a busy mix with bass guitar, kick drum etc filling up the low end then the cut will likely have to be higher than if it is just an acoustic on its own, maybe even as high as 120hz.
6. Take a listen through, if it is sounding a bit boomy then set your EQ to +10 db at around 250hz and then sweep the frequencies between about 200-400hz until you find what frequency band is creating most of the boom or muddiness ie. which area sounds worst when boosted. Then cut that frequency. I wouldn't cut too much, maybe 3-4db but it depends on how bad the area is. Don't be afraid to cut a little more if need be but obviously the less EQing you do the more natural the sound is. Aim to keep your Q around the 1.0 area. That way a whole octave of frequencies are being adjusted and the sound should end up more natural. If you have any specific annoying frequencies poking out which need cutting then feel free to use a high Q to isolate just those frquencies.
7. Depending on the style of music, a nice boost further up in the upper mids can help... Again no more than 3-4db somewhere in the 2Khz-3500 range can be nice. Be careful here though as you can easily introduce too much harshness. Sometimes a little 'air' can add a bit of sheen to the sound. A small boost in the highs can work wonders, maybe around 10khz. If you feel the guitar needs a little more 'attack' then look for something to boost around the 5khz area. Again be careful not overdo any of this.
8. Add some compression and reverb to taste. Then perhaps double track or quadruple the part if it needs it.
There really is so much you can post processing. Sometimes a little chorus is nice on Acoustic guitar, it all really depends on what you are playing and the style of sound you are going for. Regardless though mic placement is probably the most important factor and that is where you should spend most of your time. It's easy to make a nicely recorded guitar sound fantastic with a little EQ. It is also easy to make a nicely recorded guitar sound awful by overusing it. However if you have recorded the guitar badly in the first place then it will take a lot of EQ just to make it sound even reasonable and at the end of the day you can only polish a turd so much.
Hope this helps a little!
