An older person should advise his younger self to prioritize their health and well-being above all else. This means eating a balanced diet, exercising regularly, and getting enough rest. Taking care of one's physical health will allow for a longer, more fulfilling life.

Secondly, the older version should encourage the younger self to pursue education and continuously learn new things. Knowledge is power and can open many doors in life. Whether it's formal education or self-taught skills, the younger self should always be looking to expand their knowledge base.

The older person would also remind the younger self to be financially prudent. Save a portion of every paycheck, avoid unnecessary debt, and invest wisely. Financial stability provides a great deal of freedom and security in life.

Importantly, the older person would urge the younger self to nurture meaningful relationships. Family and friends are vital for happiness and emotional well-being. Always make time for loved ones and cherish those relationships.

Lastly, the older self would tell the younger self to live authentically and pursue their passions. Don't be afraid to take risks or make changes in life if it aligns with one's values and goals. Fulfillment comes from living a life true to oneself.

In summary, good advice would include prioritizing health, pursuing education, being financially prudent, nurturing relationships, and living authentically.