For example, when I do rope skipping for exercise, I usually set a big goal of 2000 skippings. Then I'll divide it into 250 parts, each of which is 8 skippings. In other words, I think I only need to complete only 250 sets, and each set is easy to complete.
Besides, I also set many milestones to tell my achievements during one rope skipping exercise. For example, I will set a milestone for every 20/25 sets.