The challenge isn't knowing what to see. The challenge is learning how to see. As soon as you learn what to look for, your originality dwindles. Your interpretation becomes someone else's.
To see well, in pictures and words, you have to know how to notice the good from the bad. Pictures speak in words. If what you see in your Instagram is uninteresting or cliche, then it may be worth skipping or unfollowing the user. If what you're reading on your Twitter or RSS feeds is banter or click bait, keep scrolling, filter that keyword, or unfollow (friends and family aside) that individual if their predictability continues.
On the other hand, if the images or words make you think or feel like you're learning something, keep tabs on that feed. A talented Instagram or a Twitter user can be equivalent to visiting a museum, reading an excellent book, or listening to an interesting lecture where there's more signal than noise.
Of course, no one's interesting all the time. There's nothing wrong with using social media to have fun. But as an overall principle, if you point your antenna to the right people, you can consume the most intriguing stories and ignore the rest.
Bonus: Watch John Berger's Ways of Seeing, and you'll never look at a picture the same way again.