Something that is common is widespread or universal. Something that is prevailing is generally current and supersedes others of its kind. The key difference is the suggestion of predominance. For instance, a prevailing view on a matter is a view that has taken over or displaced other views. A prevailing fashion is one that has caught on and emerged as the most notable or influential at a particular time.
To cultivate something is to tend to it and help it flourish. This verb is widely used to talk about tilling fields and growing crops. However, as a synonym for the more general verb develop, cultivate veers into metaphorical gardens: when we cultivate talents or skills, we refine them, perhaps with lessons or practice; when we cultivate relationships or friendships, we encourage and promote them; and when a celebrity cultivates an image, they are carefully crafting a public persona.
A goal is an achievement toward which effort is directed, such as getting into a certain college or running a marathon. An intention is what one means or hopes to accomplish or carry out. It is close to a plan, emphasizing what is held the mind as motivation or purpose. Sometimes, however, the word is meant to highlight distance between what is planned or wished for and what is put into action, as in the case of good intentions that fall short of producing an outcome.