A good singer who belts out a song with feeling and confidence will offer a better show than a really great singer whose lack of confidence results in a halting, self-conscious performance. In this analogy, Gemini, you are that really great singer, but you don't have the confidence right now to show your stuff in the best light. Before you get into a presentation or a performance prematurely because you are not fully ready, you need to build yourself up to the point where your performance will be to the
full extent of your potential.
一位优秀的歌手他会用感情和自信大声地唱出一首歌，
而且他会唱得比一位出名伟大的歌手却缺乏自信而造成犹豫、缺乏自知的演出还要好？
用这来比喻你们，双子们，你真的是一位很棒的歌手，
但是你现在没有自信将你最好的才能展现在聚光灯底下。
在你还没有完全准备好之前，就进入表演或者是过早表现（表演生涩），
你需要将自己的实力建筑到（累积到）一定的程度，
你才会完全地展现你的实力（大展长才）。
Ps.如果有误译或者是翻译得不通顺之处，请指教，谢谢。
中间打问号的地方是我翻译得不太确定的地方，请指教，谢谢。