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

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. : )