I want to convey so much more than material things to those I love. I want them to know what was most important to me in life, what I did to get through times of crisis, my guiding principles—is there a good way to do this?
Yes. What you are describing is a concept called an Ethical Will. An Ethical Will conveys your sentiments, values and beliefs in a document that you create for your loved ones. It is not a legal or binding document, but rather a written legacy of what you want your loved ones to take from the experience of your life. There is no right way or wrong way to create one or requirements that need to be included. Each one is as individualized and unique as its author.
There is much more information at the Celebrations of Life website about ethical wills and ideas for how to create your own.