I don't like watching the speed builds because they go too fast for me to recall the whole process, even when they are separated into multiple videos. I can't really find any castle blueprints either ...
I am far too impatient to try to do this in my own game, but my best suggestion would be to download some from the gallery and take a "tour". You can use the eyedropper tool to see what objects people use for various purposes. Usually when I'm looking for ideas for my builds I take a look at some examples in the gallery I like.