Hey... sorry again that it's taken me so long to reply.
Well.... you said you wanted to know about fills, styles of playing, and chords..... so I'll talk a little about each one.
Let's start with chords. I'm assuming you know how to form the basic major and minor chords.... so I'll move on to some more exciting ones.
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7's - These are incredibly useful chords, especially for adding variety to a well-known or often-played song.
For example, changing a simple minor chord to a minor 7 chord makes the sound a lot more contemporary and makes the switch from a minor chord to a major chord a lot smoother. Minor 7's are also very easy to form. Just take the minor chords relative major, and play that over the root. For exampe: Am is a relative of C major; so to form Am7, you'd take a C major chord and play it over a root note of A... A-C-E-G. It sounds really good if the chord AFTER the minor chord is the relative major... makes the song really flow.
Major 7's and dominant 7's are a little trickier and I don't use them as much. A major 7 chord takes the major chord and adds the 7th note in it's scale. For example: Dmaj7 would be D-F#-A-C#. Major 7's do basically the opposite of a minor 7. While a minor 7 gives a minor chord a slightly brighter and more "major" feel..... a major 7 gives a major chord a slightly darker and more "minor" feel. It's like taking the relative minor of the V chord of a scale and playing it over the tonic. (does that make sense?) For example: In the key of G, the V chord is D. D's relative minor is Bm. If you play Bm over the tonic (which is G), you get a Gmaj7.
Dominant 7's (usually just called 7's) are formed by taking the major chord and adding the note ONE HALF STEP BELOW the seventh note in the scale. For example: G7 would be G-B-D-F. Using the dominant 7 adds a little bit more tension than simply playing the major triad. It's really cool if you play the major chord for the first two beats of a measure and then switch to the dominant 7 for the last two beats.... and then resolve it all on the tonic. For example: Try this progression.... D, D7, G.
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Suspended (sus, sus4, sus2) chords - These are great for adding tension and sparkle. They resolve very nicely. A suspended chord basically takes the middle note of a chord (which is usually the 3rd) and replaces it with something else. In a sus4 (usually just called sus) chord, you replace it with the 4th note. For example: Dsus would be D-G-A. In a sus2, you replace it with the 2nd. For example: Asus2 would be A-B-E. One very interesting thing to note is that in any key, the sus4 of the V chord is the same as the sus2 of the tonic, just inverted. For example: In the key of G... the sus4 of the V chord would be Dsus4, which is D-G-A; and the sus2 of the tonic would be Gsus2, which is G-A-D..... Dsus4's first inversion. Switching between these two chords is particularly effective. Try playing this progression: G, D.. then Gsus2, Dsus4. Listen to the difference between the two. Now try playing each chord in the same position.... play both the Gsus2 and the Dsus4 as G-A-D, just switch the note that your left hand is playing. For Gsus2, you should have G-A-D with a G in your left hand, and for Dsus4, you should have G-A-D with a D in your left hand.
Another particularly effective trick with suspended chords is to use both versions (sus2 and sus4) along with the simple major triad. Try playing this progression: E, Esus4, E, Esus2. This technique (and variations of it) is used quite often in CCM and P&W music. One particularly good song that uses a variation of it is "My Hope Is You" by Third Day (the progression goes C, Csus2, C, Csus2)." The E, Esus4, E, Esus2 progression I gave you earlier is often used as the intro for "Come, Now Is The Time To Worship."
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Add9, add2, add4, etc chords - These are probably my favorite chords in the world. They can instantly transform a boring chord progression into something that sounds really good. All you do is exactly what the chord's name would imply, you add a note. For an add2, you'd add the second note in the scale. For example: Cadd2 would be C-D-E-G. An add9 is exactly the same thing as an add2, because if you follow the scale up to the 9th note, you'll find that it is simply the 2nd raised up an octave. So Cadd9 would be C-D-E-G as well. Add4's sound very similar to sus4's and can often be used in place of them. For example: Dsus4 is D-G-A, and Dadd4 is D-F#-G-A. Add4's can also be used in minor chords, which is really cool sounding. For example: Am(add4) would be A-C-D-E. If you add the minor 7, the chord becomes even nicer sounding. For example: Am7(add4) would be A-C-D-E-G. You can voice this by playing octave A and G in your left hand, and playing a Cadd9 chord in your right hand. I use this exact chord in "Did You Feel The Mountains Tremble" by Delirious.
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Slash chords - These are notated like D/F# or Am7/G. All it means is that you are changing the note that your left hand is playing. In a typical D chord, your left hand would play D. But in a D/F#, you would play F# with your left hand. What is particularly effective is using notes in the left hand that are not included in the chord played in the right hand. For example: Try playing a Dsus4/F#. The F# in the left hand is not played in the chord in the right hand. It is implied though from the D. For a more exotic flair, try playing completely unrelated notes in the left hand. For example: Try playing a C/B. It sounds pretty bad by itself... but put it in context with some other chords. Try this chord progression: C, C/B, Am. It adds a nice walking effect to the left hand.
Ok... I'll post some more later about fills and styles of playing. In the meantime, I hope this has helped you.