Guitar Chords in D Major
Diatonic Triads
The guitar chords in D Major are: D, Em, F#m, G, A (A7 is Dom7), Bm, C#o.
The key of D has 2 sharps (F sharp and C sharp). A good way to remember this is that this is the opposite of the key of D flat Major. D flat Major has 5 flats and they are whatever is natural in D.
So, the key of D has 5 naturals - G, D, A, E, B, so the key of D flat has those 5 tones as flats (Bb, Eb, Ab, Db, Gb). The sharps and flats for two keys related by letter name, always equal 7.
2 sharps plus 5 flats = 7. This is consistent for all keys.
The Major Keys: C G D A E B F# Gb Db Ab Eb Bb F

Practice fretting all of the guitar chords in D (Diatonic Triads) above. Keep in mind that c# diminished (the last one) isn't used much. It is good to know, but okay to forget (don't really do that).
Practice the scale. If you need help interpreting the Scale Frame in the middle box above, please consult this lesson. Memorize: t here are 2#'s in the key of D (F#, C#).
Play the Chord Scale and a progression like (I-vi-ii-V7-I or I-IV-V-IV). Notice the A7. It is also presented in a chord compare lesson.
Keep in mind:

Of these guitar chords, which is the toughest?
Like in the key of G Major, there's B minor again. B minor is in the key of D, but in location vi.
For this key, the fingering for B minor includes a bar (using the index to press more than one fret). You don't have to bar. Also, when you bar this chord, you only have to apply pressure on the fingertip and the spot on the index knuckle where the first string falls.
Another word on barring: bar only if necessary and use your bone edge (not the soft part of your inside or palm side finger).
For a chord like Bm, use your index to mute the low 6 string.

