to look long and hard in wonder or surprise
gawp
to look, especially for a short time or while trying to avoid being seen
peek
to look for a long time with the eyes wide open, especially when thinking
stare
to look carefully or with difficulty
peer
to make note of (something) through the use of one's eyes
spot
to keep one's eyes on
observe
to half-close the eyes to be able to see something
squint
to look long and hard
gaze
an instance of looking especially briefly
glance
an instance of looking especially briefly (accidental)
glimpse
a long angry look
glare