I always marvel at the fact that Jefferson was only 33 when he penned much of the Declaration of Independence. Given the importance of that document and its effect on the country and the world at the time, that is quite remarkable.
He founded the University of Virginia. His library, at one time, became the main holdings of the Library of Congress. It's also important to remember how deeply conflicted he was personally, and on the issue of slavery. It gnawed at him all the way through his Presidency.
I'd also add that was perhaps the most eloquent spokesperson for the anti-federalist cause, approached in intellectual prowess only by perhaps James Madison.
It would really be helpful if you could tell us more precisely what you are looking for. Many aspects of Jefferson's life could be seen as relevant depending on what your interest is.
A very relevant aspect of Thomas Jefferson's life, in my view, is that he was a major slaveholder. Thomas Jefferson, of course, was the main author of the Declaration of Independence. When he wrote that document, he gave the world some very stirring ideas about the equality of mankind and the need for self-government. It is therefore relevant that he was, at the same time, denying the equality and the rights of his slaves. Jefferson did not even free his slaves after his death as George Washington did.
This contradiction in Jefferson's life is very important as we think about what sort of a man he was.