What is the meaning of [Hew not too high lest the chips fall in thine eye]

Don’t be too ambitious. Realise your own limitations. Like the man who tries
to use an axe above his head instead of at a level low enough for him to use
it effectively, if you try to live above your proper station in life are
liable to suffer humiliation. On the other hand, Faint heart ne’er won fair
lady.