How do you use/ differentiate between 的、得、and 地?

的 is a possessive or descriptive particle - this means that it marks out a relationship between two nouns, or between an adjective and a noun. For example, 他的姐姐 (his sister); or 快的车 (a fast car). 

得 is also known as the complement of degree - this just means that it goes after a verb and links it with an adjective, marking it out as either a customary action, or the manner in which something is done. For example, 她跑得很快 (he runs very fast) or 他整齐卧室整齐得很清洁 (literally: he tidied [his] bedroom tidied it very clean; meaning, he tidied his bedroom very well or until it was clean). The latter sentence shows that even in a sentence with an object, the verb is repeated again so that the 得 comes right after it, between the verb and the adjective. In this case, the 得 also marks the result of the action, that is, that the room was tidied and became clean.

地 is an adverbial particle - it describes how an action is carried out, by linking an adjective with a verb. For example, 他不很认真地学习 (he doesn't study very hard), or 小姑娘大声地唱歌 (the little girl sings loudly).