Advice for Juniors

You guys had many free times during 2 years. I know that because I had experienced it. However, after I became the 3rd grade, I regret about my behaviors during 2 years. This long time was the time that I could develop my knowledges and abilities of somethings. For example, I couldn’t devleop my guitar skills and studying skills because I just played during that time.   Also they need to improve there mind toward the seniors.