set your sights high/low

set (one's) sights high

To have very high expectations or ambitions. You have to set your sights high if you want to have a fulfilling life. We had a really great year for sales; now let's set our sights even higher!
See also: high, set, sight

set (one's) sights low

To have low expectations or ambitions. My brother's attitude is that, if you set your sights low, you won't be disappointed by life.
See also: low, set, sight

set your sights ˈhigh/ˈlow

be ambitious/not ambitious; expect a lot/little from your life: If you set your sights high, you could do anything.
See also: high, low, set, sight