You may be among those of us who have taken the Myers-Briggs personality test. I found that test somewhat helpful in understanding some of my behaviors, and I've taken it several times through the years—sometimes in work settings and other times in less formal settings.
However, there's another resource that, for my money, tells me far more about myself; and that's the Enneagram. The Enneagram sorts people into one of nine personality types but also includes side wings so offers more possibilities. In addition it shows what people are like at the unhealthy end of their type, in an average state and also at the healthiest end of the spectrum. Most books on the Enneagram offer lots of pointers to help you move from unhealthy to average to healthy. Personalities are seen as more fluid, and there's more possibility for growth and transformation, which is why I am so fond of it.
Many books are available, but there's also a quick online test you can take to give you some idea of what the Enneagram is like before you invest in a book. If you just want a quick-and-dirty idea of the Enneagram, here's an online test to try. If you're intrigued by what you learn here, look online for resource books. My favorite is The Wisdom of the Enneagram by Don Richard Riso and Russ Hudson.