Welcome To Music Theory Learning: A Quick Guide To Helpful Music Theory Basics

Quick Ways To Make The Major or Minor Scales
Whole and Half Step Pattern For The Major Scale:

W-W-H-W-W-W-H

H = Half Step W = Whole Step
Examples of half steps: G to a G#, A to an A#, C to a C#, on guitar a half step is just one fret up from the last fret you were playing. The only notes that don't have a sharp when you go up a half step are E and B. The E note half steps up to F and the B note half steps up to C. A Whole Step is simply TWO half steps.
So to use the pattern to find the G major scale, you would start on the note G, then go up a whole step, another whole step, a half step, and 3 more whole steps in a row!

Whole and Half Step Pattern For The Minor Scale:

W-H-W-W-H-W-W

Works the same as the first pattern. You just pick a note (key) that you want to play the minor scale of and follow the whole and half step pattern!

TIP:
When you are playing a major scale. The 6th note of the scale is that scale's relative minor scale. Which means if you start on the 6 note you are playing a different key's minor scale that has the exact same notes in it as the major scale you were playing!
For example: The 6th note of the C Major scale is A, so the A minor scale has all the same notes in it as the C Major Scale, the only difference is you start on the A note (which makes A the tonic of the scale).

Learn 7 Scales By Knowing Only One Major Scale: Modes

Lets use C Major as an example. Depending on what note you start and end on in the C Major scale will give you a different Mode (scale). The order and names of the modes are:
Ionian
Dorian
Phrygian
Lydian
Mixolydian
Aeolian
Locrian

So starting the C Major scale on the C note gives you the C Ionian mode, which is really just the usual major scale. If you start on the D note you get the D Dorian Mode. Start on E: E Phrygian Mode. F: F Lydian Mode. And it goes that way for the whole scale following the order of the modes. Note: The Aeolian Mode of any scale is just the usual minor scale for that note!

Finding What Chords To Play In a Major Or Minor Scale:

Finding the chords to play in a scale follows a couple simple patterns. For the Major Scale starting on the root note (tonic) of the scale it goes:

Major Chord - Minor Chord - Minor Chord - Major Chord - Major Chord - Minor Chord - Diminished Chord

So for the C Major Scale the chords would go: C Major, D minor, E minor, F Major, G Major, A minor, B diminished.

For the Minor Scale starting on the root note the pattern goes:

Minor Chord - Diminished Chord - Major Chord - Minor Chord - Minor Chord - Major Chord - Major Chord

The Circle Of Fifths: A Quick Way To Find The Notes In A Major Scale:

NOTE: The C Major Scale Has No Sharps or Flats!
Using The Circle of Fifths To Know What Sharps or Flats are In a Major Scale
A couple phrases for memorizing the sharps, the first one is:

Goes Down And Ends Battles Father Charles

The above phrase is for remembering the NUMBER of sharps in a scale (the scale is the first letter in each word). For example 'Goes' is the first word so there is 1 sharp in the G major scale. 'And' is the third word so A major has 3 sharps! IMPORTANT: The last two words: 'Father' and 'Charles' stand for the scales F# Major and C# Major not F and C natural.
What you do next is use the second phrase to figure out what those sharps are:

Father Charles Goes Down And Ends Battles

So we know that A major has 3 sharps so we use the 1st 3 words in the SECOND phrase, and the first letter of each word will be the sharps. So for A Major: 'Father Charles Goes', A major has an F#, a C# and a G#.

NOW for the flats there are 2 more phrases that work the EXACT same way. To count the NUMBER of flats in the scale use:

Father's Battle Ends And Down Goes Charles

IMPORTANT: The first word (first letter) in this phrase is the only natural scale and the rest are flat scales. So for F Major (first word 'Father's') it has 1 flat. The second phrase for flats:

Battle Ends And Down Goes Charles' Father

So we know F Major has one flat so that flat is a B flat ('battle'). The E flat scale would be the 3rd word in the FIRST FLAT phrase 'Ends' so the E flat major scale has a Bb, Eb and an Ab. TIP: Another way to remember which flats there are in the scale is to remember B-E-A-D or BEAD and then GCF.

Whew, if you made it through that and are starting to understand it you're well on your way to music theory greatness! I recommend writing the phrases on some cards and doing your best to memorize them (or even come up with your own)!