Almost same as the first answer. 发挥 emphasizes on "to show sth. which the subject already has" i.e. A medicine can cure your illness. If it works, you can say 药物发挥作用 ( the medicine works). 实现 equals "to realize sth, to make sth. happen" The subject does not know if he is capable of doing that. i.e. 实现梦想 (makes dream come true) : )

发挥在于你本身就拥有的someting 发挥我最佳水平 实现在于你本身而没有的someting 比如实现愿望

The first sentence would be better, although people also understand what you say when you use '实现效果"。 实现 means to achieve or to implement. 实现理想/梦想/目标 achieve your dreams (实现你的梦想)，achieve the goal(实现目标) 发挥 means 发挥天赋/作用/优势/效力 发挥你的天赋（exert your talents）