That's a great way to remember them redstrawberry. Because e.g. stands for "exempli gratia", a Latin phrase meaning "for example" and i.e. means "id est" another Latin phrase meaning "in other words". So unless you can remember the Latin they're harder to remember.
Don't really see the difference. If you are clarifying something, aren't you just giving an example to make it more clear? Or if you are giving an example, isn't that just to clarify what you mean?
i.e= in essence