How to solo over progression E-A-F-Em

I'm attempting to learn a bit of theory to help my guitar improvisations, but one thing I am struggling with is what I could play to go well with the chords of rhythm guitar that i'm playing to.

At the moment i'm playing to a track strumming a sequence of E A F Em chords.

Where to from here with the lead?

Dugggy

Knowing what key center(s) the chords create is a good start. It does not always tell you exactly what scales or notes to use because of stylistic variations.

E A F Em

There is no single key that fits all these chords. There are at least two keys.

First let's look at E and A. You can fit both into one key.

E and A can be the "I" and "IV" in the key of E major. E and A can also be the "V" and "I" in the key of A major.

Depending on the style you could start with either the E or A major scale or the E or A major pentatonic scale.

E major: E F# G# A B C# D# E major pentatonic: E F# G# B C#

A major: A B C# D E F# G# A major pentatonic: A B C# E F#

I like the second choice (A major or A major pentatonic) because the upcoming F chord does not fit as easily with an E tonal center, even though that's the first chord. E as the tonal center would require a modal approach in the next two bars, which is not the first thing you want to learn. (It'll be the second thing!)

---

Now to the chords F and Em.

These may be the "vi" and "V" chords in A minor.

So to get a really simple solid approach to playing in a non-jazzy way over the progression, try just playing:

A major or major pentatonic for the first two chords, then A minor or minor pentatonic for the second two chords.

There are many other ways to do it, but this is a good start that lets you concentrate on your phrasing rather than jumping through lots of scales in your head.

---

The source of this thinking is knowing how to find all the chords in a key center. This is done by harmonizing the scale.

You create the chords I-vii by stacking 3rds above each note.

If the scale is A major: A B C# D E F# G#

it produces these chords:

I           A C# E    (A)
ii          B D  F#   (Bm)
iii         C# E G#   (C#m)
IV          D F# A    (D)
V           E G# B    (E)
vi          F# A C#    (F#m)
vii         G# B D    (G#dim)