Watch the Day 15 online guitar lesson by Ravi from Learn Guitar in 21 Days
Mixing major and minor chords is a common songwriting technique, and C major and A minor are frequently played together. Not only do they sound good, but you only have to move one finger to make the change. So, set yourself up for C, and then only move your third finger in order to shift to Am. Make sure when you return to C that you stretch your third finger toward the end of the fret, as that will greatly improve your sound.