raise one's sights

raise one's sights and set one's sights high (to try to get something better than you had originally expected) — поднять планку; повысить уровень притязаний или требований; рассчитывать на большее (чем предполагалось)

Example 1: This year we will add resources to encourage young people to stay in school so more of America's youth can raise their sights and achieve their dreams.(CNN Event)

Example 2: A minority of self appraisers will under or over rate themselves, but this quickly shows up. The under raters need encouragement to raise their sights and reach for the apparently impossible. (Twenty ways to manage better. Leigh, Andrew. London: Institute of Personnel Management, 1992)

set one's sights too high — слишком высоко метить; слишком на многое замахнуться; слишком губу раскатать; слишком многого хотеть (общее:чрезмерность и нереалистичность желания)

Example 1: I think they set their sights too high – they'll never find someone for the job who has all those skills.

Opp.
[lower one's sights]