Warming Up with Alternate Picking
The following figure is good for working on alternate guitar picking and getting to know the placement of the strings under your picking hand. Set your metronome to a comfortable tempo and rehearse the figure for a minute or two. Aside from moving across the strings in the two directions shown, you can use random movement and skip strings.
To sound more musical, hold down a chord shape with your fretting hand. For more of a challenge, the same exercise can be played using sixteenth notes.