Some writers depend on italics instead of the rich pool of language available and that can dilute the prose. Look for ways to create emphasis through word choice or sentence structure. For example, this line relies on italics:
She had to leave.
But this version, which uses the more precise verb—stumbled—and accomplishes that emphasis as well as the nature of her urgency:
She stumbled past the hostess and, finally, the glass was door only inches away.
You can also use italics to create an effect. Daniel Orozco does this in his short story “Orientation,” in which a new employee is getting a tour of the office:
This is the microwave oven. You are allowed to heat food in the microwave oven. You are not, however, allowed to cook food in the microwave oven.
The use of italics brings attention to this distinction between heating food and cooking it, highlighting the absurdity of the rules in this office, and the degree to which they manage minute details.
Save italics for the moments when the formatting really adds the extra oomph a word needs.