The word glance is usually succeeded by two prepositions, at and over. Nevertheless, being ignorant to their particular fields of usage, many students of English often mess things up.
To glance at is to take a hasty look at something. The usage may also imply to touch on something lightly as in a speech. On the other hand, the phrasal verb glance over also means to look at something in haste. Nevertheless, apart from this, the phrase glance over also means to peruse casually, like taking a glance over a book or a catalogue or the like.
1. I glanced at his face but could not recognize him; he seemed to me none but a stranger.
2. Keep this newspaper article for record, it glances at business success.
3. Just take a glance over this.
4. I showed him the article but he did not show much interest, and merely took a glance over it.