Even though up to this point I haven't explicitly written out to what you should set your metronome to, you should be using one whenever you practice any of the guitar techniques on this site. I'm going to go over a few exercises that will show some ways to implement a metronome into your scale runs and chord changes. Have fun and play around, experiment. Keep this in mind though.
Do not sacrifice clarity of tone for speed. Always work your way up to your fastest, clean playing. Practicing slow with a metronome will ensure that your muscles remember the correct form and position to get clear tone. The speed will naturally come. The following exercises are not designed for creativity, only for examining a way to use the metronome. If you are already familiar with it, simply move on.
Guitar Technique: Metronome with Chord Changes
These exercises are very simple. Later in the Songwriting section when we talk about rhythm we'll take a more thorough look at the use of the metronome with chord changes and the specifics of quarter, eighth, sixteenth notes, etc. It's such a useful tool there will certainly be future studies for members in the coming months that dive into the nitty gritty of its use. For now take these exercises and play around, test your speed, experiment with rhythmic changes for the chords or emphasize different beats for the solo exercises. Thanks.