Avoid “physical appearance” descriptions that violate viewpoint perspective.

Example: Your character is an attractive redhead with green eyes. The man she is falling in love with enters the room and makes eye contact with her. It's her viewpoint and you’ve written something like this: She blinked her emerald-green eyes and smoothed back her coppery ringlet curls.

Who thinks of themself in such a conceited manner?

What you should write is simply this: She blinked her eyes and smoothed back her hair.

“But,” you say, “I want the reader to envision her pretty eyes and vibrant curls.” No problem. Create the image through his perspective - not hers. Find an opportunity in the same scene or chapter to switch over to his viewpoint. Have him notice and think about her “emerald-green eyes” and her “coppery-ringlet curls.” This way, you get the description out that you want without making your character egotistical.