There have been lots of suggestions and input given by people to make you more useful while on the forum, so what you should focus on is learning a few things based on the suggestions and input that have been given by these people. I guess it's something you can learn slowly to get you to the discussion skills stage, just be yourself and don't follow the habits of people you can't learn perfectly, find what you master slowly because it will help you develop.

Knowledge will lead you to a constructive discussion stage and the more you read the more understanding and insight you will gain. Knowledge is one way that can push yourself to grow more in the forum, what you need is consistency to learn all that slowly.