Well, it looks like you got most of it under control. Here are a few tips on the wiki.
a) <pre>text</pre> will put the text in a fixed format like you would expect from PRE tags.
b) In normal mode, if you start the line with a space character, it pushes the formatting into the same fixed format mode, but also allows other things like bold/italics/strike tags. The "starting the line with a space" is the critical part.
c) If the line is started with any other character, it is treated like free flowing html.
d) If the line is empty, it will break two fixed format boxes apart, or put in a separator line between them.
e) Using the Source vs. Visual editor on the top right of the edit box will help immensely to show you the differences in tags and style formats.
Yes, wiki formatting is very ugly and inconsistent. I am an expert and I still get quite annoyed with it. So, if there is something you want, just ask and I will gladly tweak the page to pound it into submission.