[elgenie]

My mnemonic is "i.e." = "in essence" and "e.g." = "example given". The real phrases being abbreviated are, of course, the Latin ones.

[Brian-Puccio]

Mine mnemonic is use e.g. when you could say “for eg-zample” and use i.e. when you could say “that is” — ie to is. Admittedly, the second half isn’t as good as the first. : )