In an attempt to sound more formal, writers tend to use i.e. or e.g. when giving examples. Although these Latin abbreviations can sound a bit lofty, it is still perfectly fine to use them, as long as you are using the correct one. There is a difference between them; they cannot be used interchangeably.
The abbreviation e.g. stands for the Latin exempli gratia, (that's "for example" to you and me). It is followed by one or more examples. Perhaps a better way to remember this one is to think of these letters standing for example given . Just keep in mind that using "e.g." does not indicate that the list given is a complete one.
"We'll be happy to have you join us for a Thanksgiving feast, e.g., barbecued turkey, cranberry sauce, wilted Spinach salad."
"The family has lots of groovy activities planned for our post-meal time. E.g., touch football, television viewing, and power napping are always popular activities for a Thanksgiving night at the Smith residence."
The abbreviation i.e. stands for the Latin id est, which means "that is." It is followed by an explanation. Not sure if you should use "i.e."? Replace it with in other words and see if your sentence retains the original meaning. If it does, "i.e." is the abbreviation for you, in that case.
"That great American holiday, i.e., Thanksgiving, is almost upon us. - Enjoy your roast turkey, green bean casserole, mashed potatoes, and homemade gravy on November 23rd, i.e., Thanksgiving."
With either one, remember to
Use a period after each letter. They are abbreviations.
Either abbreviation can be used to begin a sentence; remember to follow with a comma.
Either abbreviation can be used in a parenthetical statement; again, remember to follow with a comma.
If using within the sentence, and not at the beginning or in parentheses, always precede and follow with a comma.
In a casual setting of course, you can just say "for example" and "that is." After all, throwing around bits and pieces from a dead language in relaxed conversation can sound a tad pretentious "Oh, in situ", utterances such as i.e. and e.g. have the ability to make the speaker sound like they have a very impressive "modus operandi!". But it couldn't hurt to know the difference between this oft-confused pair, especially if you use examples and rewordings often in your writing.