El Cabron said:
ok
for example A-minor:I-IV-V
sometimes I use more complex chord progressions,but usually I stay with 2 or three chords...
Secondary dominants can spice up simpler chord progressions. Pardon me if I get into stuff that you already know.
In that I-IV-V progression, the V is the dominant chord and resolves nicely back to the I. A secondary dominant chord is the V of any other chord in the progression besides the I. For example, 'G7' would be the V of Dmin(the IV in your progresson). And 'A7' would be the V of Emin. You could put those subdominant chords in front of the Dmin and/or Emin. For example: Amin-G7-Dmin-A7-Emin
Substitutions are another way to get some variety. The I is obviously the tonic. The III and VI are also tonic in function. You can substitute those for the I at any time. For example: Amin-Dmin-Emin-Cmaj-Dmin-Emin
The IV is subdominant. The II is also subdominant. You can substitute. For example: Amin-Bdim-Emin
It's also very common to borrow diatonic chords from the other minor keys... harmonic minor, melodic minor, dorian. The 5th degree of the harmonic minor is a dominant chord... E7 in Amin. So you could do: Amin-Dmin-E7
And you could use any combination of the above. Amin-Bdim-E7-Amin-Dmin-C7-F maybe.
El Cabron said:
from time to time I try to break out of the triads and use 7th or 9th chords
Extentions will add spice too. Try saving the longer extensions for the chorus or bridge for more contrast.
El Cabron said:
but it still seems boring after a time...
is there a way to leave the scale just for a short time and come back(maybe using a diminished or augmented version of the scale)??
Changing scales and changing chords/keys are 2 different things. Assuming you mean change keys, you could modulate for variety. Common modulations are to the relative minor/major or to the parallel minor/major.
So, from your Amin progression you could modulate to Cmaj. Try going to G7 for your last chord of the verse, then to C as the first chord of the chorus and continue in Cmaj for the chorus. For example: End of verse... Dmin-G7 --> Chorus Cmaj-Fmaj-G7
Or you could modulate to Amaj. After E(V), go to Amaj instead of Amin. So: End of verse... Dmin-E7 --> Chorus Amaj-Dmaj
Now, if you just want to change the scale, you could add color tones to A natural minor, you could play A minor pentatonic, A Blues, A Dorian , A harmonic minor, any of the modes related to Amin/Cmaj. Just try not to lean on the non-diatonic tones for too long, and end your phrases with scale or chord tones.