Man doesn't form its plural in the regular way, that is by adding an -s, and advice is a noncount noun.

Correction: The men in her life gave her very bad advice.

Check the following resources for useful practice material: 1) Guide to Grammar and Writing, 2) Colleen Hildebrand's UCI Correction Symbols with hyperlinks.

For more concerning mass and noncount nouns, consult the LARC Electronic Writing Center Grammar Checklist