There are many words and phrases that can be used as synonyms for "give one's best." Some common options include "exert oneself," "strive," "put in maximum effort," "do one's utmost," "go the extra mile," "give it one's all," and "put forth one's best effort." More informal options might include "give it your all," "do your best," "put your heart into it," or "give it your best shot." Some synonyms focus on the idea of exceeding expectations or reaching one's full potential, such as "surpass," "excel," or "outdo oneself." No matter which synonym you choose, the goal is to convey a sense of putting forth great effort and achieving success.