you always set your sights high (plural).
It means that you try to do your very best or try to achieve
something that is beyond what you might ordinarily be capable
See this, from thefreedictionary:
set your sights (on doing something)
to decide what you want to get or achieve something. I think they set their sights too high - they'll never find someone for the job who has all those skills. Once she sets her sights on something, she won't stop until she gets it. I hear she has her sights set on becoming a journalist.