* Adding a noun or noun phrase: "In addition to her singing, she plays the piano beautifully." Here, it adds another talent to her abilities.
* Adding a verb phrase or clause: "In addition to studying hard, she also volunteers at the hospital." This adds another activity to her schedule.
* Adding a list of items: "In addition to apples, bananas, and oranges, the fruit basket contained grapes and kiwi." This expands the contents of the fruit basket.
* At the beginning of a sentence: "In addition to the cost of the car, you'll have to pay for insurance." This emphasizes the extra cost.
* In the middle of a sentence: "She enjoys hiking, and, in addition to that, she loves swimming." This adds a second hobby.
* At the end of a sentence: (Less common, but possible) "We need milk, eggs, and bread; in addition to those, we also need cheese."
The key is to use it to introduce something that complements or adds to what's already been mentioned. Make sure the added element is grammatically consistent with the rest of the sentence.