Harmonics are the bell-like tones you can get by touching the top of a string. This guide, from an article by Ray Mitchell in Guitar Magazine March 1973, describes the techniques used by classical guitar players to get harmonics on open and fretted strings.
Gary Shutt shows how to get the low 7 string sound on a normal 6 string, using B standard tuning. What you need to do is get yourself some really thick and heavy gage string like 13 through 56 or a 7 string set and just not use the 9. Once you have your strings on, you tune everything down to perfect fourths. Going from the lowest (bass) to highest strings you will have: B-E-A-D-G-B.
So both of your outer strings will be B's and they will have the same lowness and chunkiness as a 7 string without the high E string. You can play your normal 6 string chords this way.
You have sketched your ideal guitar shape, it looks good on paper but will it work full size? Berlin guitar blogger GuitarRen has designed some great guitar shapes. GuitarRen tested his designs with cardboard mock ups, painting them and adding aluminium foil. He even added pickups and control knobs. This is a great way to test a design before starting to build. I think the one on the left is best, the long lower horn should give it good balance and ergonomics.
Changing strings can be daunting for new guitar players. There are many ways that you can do it, especially the bit where you secure the string to the tuning peg. Is there a right way to do it? Dan Cross of about.guitar.com thinks so. Have a look at his step by step illustrated guide to changing strings on an acoustic guitar.
Drop B tuning is an alternate tuning for a six string guitar used by metal guitarists to achieve a deep and powerful sound. To get this low 7 string sound on a normal 6 string you need to do get yourself some really thick and heavy gage string like 13 through 56 or a 7 string set and just not use the 9.
This is a useful instructional video for absolute beginners on the guitar. Jeff Isbell shows how to play the basic open chord shapes, E-A-D-G-C. Jeff gives a few fingering alternatives for the basic shapes.
This is another video guide from Gary Schutt, about the basics of reverb. Reverb effects create a copy of the incoming signal slightly time-delays it, making it sound like you are in an echoing room. By varing the delay and volume of the echo, you can sound as if you are playing in a phone booth or a cathedral
Palm muting is a common technique in rock guitar playing. Resting the side of your palm on the guitar bridge gives a percussive quality to distorted chords. The trick is using just the right amount of palm pressure: too much and you wont get any sound, too little and you will loose the chunkiness.
Have a look at this video from Gary Schutt . Gary has a degree in songwriting from the Berklee College of Music and has written over 150 songs, has 5 CD's, and 1 DVD currently available.