Personal development comes in a wide variety of activities, but it has been my experience that you have to actively want to change yourself before anything can be done. From there, you are able to grow and learn from your experiences. This will aid in all aspects of your life, from the home to the work place.
The ability to look in on oneself and see where you fall short is a hard thing for most people to do. It took me years to figure out that I needed to change and even longer to actually make the change a set reality. Often times, the need for change comes from a dark part of your life, but you may be lucky enough to have insight or others helping you to know where you need to improve.
The path to personal development can be long and hard, but that isn't to say you won't have fun in the process. If you enjoy reading, there are thousands of books that can help you for whatever aspect of development you want and need. You may not realize it, but the books HR speaks about to staff often have great truths hidden within them, as long as you are willing to accept the advice.
It has been an ongoing process for me to develop, both personally and professionally. In fact, it even involved a bit of therapy early on to learn self-coping skills after a long stretch of depression. Hearing about my faults wasn't easy, but ten years later, I understand what my therapist was telling me and that helped, at least for a while.
Like in anything, you stagnate and think that everything is better even if things are worse. This happened to me as well, as I'm sure it has happened for many others. The key is to always reflect on yourself whenever things are both going well and badly. This combination of reflection gives you a solid look into what happens in your life, and more importantly, it shows how you react.
Take these reactions and build on them. If you are too angry, try to find a way to dissolve your anger before it blows up. Some cry too easily, and you can take this observation as a wake-up call to toughen yourself up. These skills will help with your spouse, coworkers, and your boss during the tough times.
If you're having a hard time tapping into your emotions, and don't have the insurance for a therapist, finding a nonjudgmental friend might be good for you. You two can speak about what problems you are having, and they might be willing to help. Just be careful not to overburden them, and strike a balance of give and take before pursuing this option.
With the right mindset, humans are able to move mountains. If your boss or a loved one sees a change in you for the better, you will want to continue to try and grow, and the cycle will continue. Don't be discouraged, and allow yourself a better life.