One very useful thing to know is the note names of the open strings. They are often used to describe finger placement (as in put your first finger in the second fret of the A string) and are also useful for tuning your guitar to another instrument (like a piano). It is needed to buy new strings for your guitar (can I please have a D string) and can help you know the notes you are playing and may help you use a guitar tuner. So well worth learning this one.
So what are the notes?
1st string - E (the thinnest)
2nd string - B
3rd string - G
4th string - D
5th string - A
6th string - E (the thickest)
Rhymes in the times
This can easily be remembered using a rhyme... like:
Easter Bunny Gets Drunk After Easter
The notes names from thin to thick strings). This is the one I was told as a kid and still remember to this day, but feel free to make up your own. If you come up with a very funny one please let me know and I will add it here.
Other Examples of rhymes...
Every Boy Gets Dizzy Around Elle (tribute to supermodel Elle MacPhearson by me)
Even Brainy Gits Don't Always Eat (...whatever man, make up your own....)
Eager Boys Go Down After Eloping (ooooh matron)
They can go the other way too - using thickest to thinnest strings like these:
Easter Angels Don't Give Broken Eggs
Eddie Ate Dynamite, Good-Bye Eddie (from James via Max)
Go for it and make up your own!