i.e., and e.g., are abbreviations for Latin terms:

i.e., stands for id est and means roughly “that is”
e.g., stands for exempli gratia which means “for example”

As these abbreviations have different meanings, it is important to use the correct one throughout your writing. Here are a couple of ways to remember the difference:

Don’t really worry about the Latin meaning, instead think of in other words for i.e., and remember the i’s match then connect the e in e.g., with example

Another way is by imagining that i.e., means “in essence,” and e.g., sounds like “egg sample” that is a good memory trick as well.

Let’s use each of the abbreviations in a sentence to give you a better sense of how to use them.

As e.g., means “for example” you use it to introduce an example:
Carla likes card games (e.g., bridge and crazy eights). As e.g., was used, you know that bridge and crazy eights are just two examples of card games that Carla likes to play.

As i.e., means “in other words” you use it to introduce a further clarification:
Carla likes to play cards (i.e., bridge and crazy eights). As i.e., was used, you know that Carla only likes to play bridge and crazy eights.