Welcome to the Guild Strado! Your enthusiasm is contagious, I am sure you will make a wonderful GM. As to refining your skills at map-making, you have definitely come to the right place. There are many fine tutorials here (in the tutorials section) that will help you to refine your skills and to learn new tips and tricks. Feel free to post up any of your work, and don't be embarrassed at all, while there are some incredibly talented artists here, we are a community of widely mixed talent and skill, and a big part of what we do is help each other grow and improve. Look forward to seeing your work.