I have decided that I will update this within the next week (or couple of weeks, hopefully, my hard drive failed and I don't have a computer with Blockland).
I will make a lot of improvements over the original tutorial and either repost it or edit this topic. I feel this tutorial doesn't deserve a sticky... yet...
Thus the coming update. I want the mod community to be able to rely on a quality GUI tutorial so GUI's don't end up looking like the one in the example I made. I've been wanting to update this since when I made this, I too was just beginning GUI's and I am better not only at creating GUI's, but I am much better at scripting and programming than I was back when this tutorial was originally made.
I will post more information about the update later, when it's not 12 AM.
Edit:
Not 12 AM anymore.
I have some ideas as to what I want to improve and add to the current Tutorial, but I think it would be better to allow you guys to tell me what you need help with. Post your ideas in this thread and I'll try to cover most of the ones I think are worth the effort.
I want to include topics like key binding, creating custom bitmap buttons, creating custom controls (I believe this is possible, can't check yet) and more. But I really want your feedback.