In the last chapter I told you to use new resources if possible or create your map based on a texture pack but I missed something that is very important: Don't limit yourself to this texture pack because that autimatically limits your creativity. If you are in the need of special resources like textures, sounds, sprites or anything else to make your "idea" really look good, try to create them on your own. And if you fail, look for it in the internet and other resources and wads. And if you fail once more, ask for it in the community forums. My experience tells me that there are many nice persons around who are glad to help you in any way, just ask for it.
Summary: "A one man project is always a hard thing, but don't limit yourself on your momentaneous skills, ask for help or learn something new!"