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.