open your account page. click on "following" on the top menu.
Then, you will see the list of people you are following with unfollow option. Also, by clicking on the account icon or name of the people you are following will open that person's boards. There is follow/unfollow option button on the bottom of the each boards. That way, you can follow only the boards of your interest or unfollow some of the boards only.
My interest is jewelry so I usually follow jewelry related boards only.
