What this silly sentence and the names of guitar strings diagram will teach you is essential.
When you look at all the things to learn, you might think it's impossible; it's like trying to "Eat A Dog Gone Big Elephant!"
Once you remember this silly sentence: "Eat A Dog Gone Big Elephant!", you've learned the guitar string names!
Pluck the strings, starting with the 6th string(the fattest string), one at a time while saying; "Eat A Dog Gone Big Elephant". Pluck them again, saying the first letter of each word out loud: "E-A-D-G-B-E".
Repeat until you remember, or you'll find another mnemonic below the diagram.

Here's another mnemonic to help you learn the names of the guitar strings. It also starts on the 6th(low E)string:
Now that you know the names of the guitar strings check out these lessons: