How can I effectively use a capo on my guitar to play in different keys, such as E major, without having to change my chord shapes?

To play in different keys using a capo on your guitar, place the capo on a fret that corresponds to the desired key. For example, to play in E major, place the capo on the 2nd fret. This will raise the pitch of all open strings, allowing you to play in E major using the same chord shapes as if you were playing in D major without the capo.