How to Improvise Great Solos on a Guitar

Ever wanted to rip an amazing solo like Hendrix? Tried to fit notes together to fit a backing track but it doesn't work? Then this might just be the instructable for you!
It will cover:
Basic Pentatonic scales to go around
Blues scales
Advanced Jazz scales
And other techniques that may come in useful elsewhere as well as here

I took some pictures myself but found others on google.

Step 1: Basics

Before I go straight on to scales, I am going to tell you about how to get the right notes to fit a particular chord, and also the circle of 5ths. If you know these, skip to step 2.

Generally, The songs you will improvise too will follow a widely used chord progression pattern, which should stay the same for most of the tune or just for a section (chorus, verse, bridge etc.)
I am going to give you notes that will fit into the particular chords. This will work with MOST styles of music, but not for others. You don't have to follow this, it is just to give you an Idea of what will fit.
Note: the following chords can be moved up or down, with the notes. you will have to compensate for the accidentals/key sharps/flats that are going to be added.

Chord: cmaj (C major)
notes that will fit: C, E,F,G,A,Bb. D and B can be used as connectors, but not too often. Do not hold these for over 1 beat or so.
Chord: cm (C minor)
notes that will fit: C,Eb,F,G,A,Bb. D and B can be used as connectors, but not too often. Do not hold these for over 1 beat or so.
Chord: Cmaj7 (C major 7th)
notes that will fit: C,D,E,G,Bb. Other notes should not really be used often if at all.
Chord: C4 (C 4th)
notes that will fit: C,F,A.Other notes can be used but not too often.

Circle of 5ths.
Sounds complicated but actually isn't. Look at the picture for details, but the main idea is to show the flats/sharps in each key. I cannot teach you the circle of 5ths, you have to learn most of it yourself. Hopefully the diagram will explain a lot.

Step 2: Pentatonic Scales

At last, a scale to learn! This can be used for most styles.
Look at the diagram for details on finger positions.

Take position 1 eg. E minor. This scale, shown below, is E minor. To make a E major, move your hand down to the nut keeping the position the same. So it makes:

|------------------------------------------------------0---3---|
|---T---------------------------------------0---3-------------|
|---A------------------------------0---2----------------------|
|---B---------------------0---2-------------------------------|
|-----------------0---2----------------------------------------|
|--------0---3-------------------------------------------------|

Which is the G major pentatonic scale as well. So, by moving the position down by 3 frets, you turn a minor into a major.

Step 3: The Blues Scale

The blues scale is used in jazz, reggae, hip hop and other styles derrived from jazz.

|------------------------------------------------------0---3----|
|---T---------------------------------------0---3--------------|
|---A------------------------------0- 2-3---------------------|
|---B---------------------0---2--------------------------------|
|-----------------0- 1-2---------------------------------------|
|--------0---3--------------------------------------------------|

It adds accidentals to the original pentatonic scale, and lo and behold, a new scale for more genres of music. Sometimes, in rock/metal music this may be apropriate too, such as songs that rely on fast broken chords and use a lot of different notes.

Step 4: Other Jazz Scales

Mixolydian
A mixolydian scale is where you add a sharp (the next one in the circle of fifths rule) or take a flat away (the previous one in the sof). Eg: C Mixolydian would have an F# instead of an F, F Mixolydian would have no Bb. If the scale has no sharps/flats, then add a sharp.

Lydian
A Lydian is the opposite of a Mixolydian: you take away a sharp or add a flat. Eg. G Mixolydian would have no sharps, and F Mixolydian would have an added Eb. Again, if the scale has no sharps/flats, you would add a flat.

Dorian
A dorian scale uses the key signature of the tone below the key note. Eg. A C dorian would have a Bb key signature (Bb and Eb).

I personally don't use a major scale, you can If you want. For major keys I move the minor pentatonic scale is moved so that the 2nd note on the 6th string is playing the tonic note.

I searched and searched both for diagrams on the internet and my book of scales, but I couldn't find them. No pictures for this step.

Step 5: Now, to Improvise! :D

Yay! Now all of the theory is out of the way, lets get improvising! :D
Firstly, get to know the backing track. Quite a lot of tunes have a similar chord progression, like a lot of blues/jazz music has 12 bar blues, but metal/rock music tends to have a more original chord sequence. Then, get notes to fit to the chord. I might make a video of me improvising to a blues song, a jazz song,and a metal song below, so if you want to see how to do it, just ask and I will make one.
I cannot teach you to improvise, it is something you have to learn for yourself.

Quote:
I can only show you the door. You have to open it.
Morpheus, the Matrix.

Another thing that may be useful is finding what guitarists you like, and possibly imitate their style (or at least take a leaf out of their book). For example, I base some of my solos on a hint of Hendrix, but its mostly from me. My jazz solos are more just from me, but do what you will.

Good luck, get to grips with improvising before you go out and show people. You have to develop your own "Style". I tend to keep the same position for the whole solo, finding the right notes to fit the chord. Some people change their scale position according to the chord. Choose which one you find easiest. Also once you get used to improvising simply, try adding phrasing to make your improvisation have that finishing touch. Now go forth, improvise, spread the word of music, and learn!