The Bend is by far the most used guitar trick in the book. As this picture shows, the trick is to push the string with your fingers while fretting it (bending the string). Usually you bend strings with your ring finger, using your middle and index fingers to help. The string tension increases, changing the sound of the note. If you pick the note and then bend the string, you get the classic wail of the Blues guitar.

Palm Muting is another way to get distinctive sounds out of your guitar. Although it works best on an electric guitar with distortion effects - it can also be used on acoustic guitars. Simply allow the palm of your right hand to touch the strings while you are strumming or picking the strings - this creates a flat sound or thump (depending on your gear). On some acoustic guitars that have excessive bass (the fat E string sounds too loud), you can partially palm mute by only touching the high E string - this will reduce the bass effect when you are strumming chords.

Guitars are normally tuned to E-B-G-D-A-E notes - however you can also use Alternate Tuning. This changes the open notes for one (or more) strings, completely changing the sound and of course the way you play notes. One popular alternate tuning is the Drop D tuning, where the high E string (fattest E string) is tuned down to D instead of E. Some rock and blues songs use alternate tuning - if you are trying to play one of those songs from tab or sheet music, it would be almost impossible to do so without changing the tuning of your guitar.

The Hammer On is another popular trick. When a note is following a previous note by one or more frets, instead of picking the second note - slam your finger down on the next required fret (while holding the previous note). This changes the note to the fret you have hammered on, and gives a forceful tone to the change. The complementary technique to this is the Pull Off, which works in reverse. When you have a note that precedes a previous note by one or more frets, fret the second note while keeping your previous finger down (don't pick the string) - then forcefully "pull" back the previous finger. The trick is to remove the finger rapidly so it doesn't muffle the string vibration - the result is a forceful note change to the next note. In guitar tab, hammer on and pull offs are marked with an arc linking the frets - if its going to a higher numbered fret then its a hammer on, if its going to lower numbered fret its a pull off. A combination of both the hammer on and pull off is called the Trill - where you rapidly hammer on and pull off on the same fret several times (keeping the first finger in place throughout). This creates an undulating sound that combines both the notes.

These are only a few advanced guitar techniques, click if you need a refresher on Beginner Guitar Lessons.

But what are those sounds called? Music has seven notes which are:
A B C D E F G after which it repeats A B C D E F G at a higher pitch (the higher pitch sound difference is called an Octave).
The spacing between each note is called a Whole Step (think DO RE MI FA SO LA TI), a distinct sound difference in the tone of each musical note. Halfway between music notes there are Half Steps:
A A# B C C# D D# E F F# G G# the # symbol is called a Sharp.
Note that half steps are also called Flats:
Ab A Bb B C Db D Eb E F Gb G the b symbol is called a Flat.
You will notice that between the B and C, and between the E and F there are no half steps, these two exceptions are only a half step apart in their normal form. The sharp and flat names can mean the same thing, for example after the A note the half step can be called either A# (A sharp) or Bb (B flat). If the half step FOLLOWS a note, it is sharp - if it comes BEFORE a note it is flat:
A (A# or Bb) B C (C# or Db) D (D# or Eb) E F (F# or Gb) G (G# or Ab)

The next section teaches Basic Guitar Chords. Chords are sounds created by combining notes simultaneously and are the basis for both rhythm and much of lead guitar. But your hands and fingers must be sufficiently trained, and you must know the individual string notes, before you can play guitar chords - so keep practicing!

Auditorium: One of the largest guitar bodies being made today. As the name implies, the sound emitted should fill an auditorium. Keep in mind, larger bodied guitars lose their projection capability, the sound seems to become lost in the larger cavity of the instrument. Yes, it will have a large sound, and tremendous bass response, but seems to lose in projection. Great for fingerstyle.

Orchestra: Little larger than the 00 and 000 models described below, the OM shares many of the same characteristics as the 00 and 000 models. New variations are now available, such as the OM Jumbo which larger than the standard OM but smaller than the Dreadnaught.

The final size, which isn't a steel string design, is the Classical sized guitar. This body size is specifically designed for nylon strings and is almost always fingerpicked. On rare occasion, players will flatpick this style of guitar - such as Willie Nelson and Jose Feliciano has aptly done. And, when guitar is played in an Orchestra setting, the nylon is the guitar of choice.

There's also the question of shallow or deep, all Dreadnoughts, and Classicals, have a deep body, more depth adding to the overall cavity of the instrument - this usually contributes to a deeper resonance and more resounding bass shallow guitars, those with less depth on the body, will have more projection and focus while also having a better balance from bass to treble. Shallow body styles are normally found in the Concert size or OOO/OO sizes.