Watch the Slow 6/8 Blues online guitar lesson by Vicki Genfan from 30 Strumming Patterns You MUST Know
Simple but profound - I'm using an Em-Am progression for this slow blues in 6/8.
The first stroke is your root on the downbeat of 1. The next stroke is a strong, solid hit on the 4th beat. Play this as a staccato - which requires the left hand muting. Take the time to get that mute accurate and clean. Remember - depending on the chord you're playing, you'll have to do different things with your left hand in order to get a proper mute sound happening.