I am still a newbie as far as using CSS is concerned. I had a problem, now resolved, where the CSS for part of my website was not working. I just couldn't see what was wrong! Eventually after a sleepless night and a search on the Web I solved the problem myself.
The reason it was not working was I had used #outerwrapper when I should have used #outerWrapper.
What I am proposing is to compile a checklist of errors and also some tips to avoid those errors. Here's a start.
1. check the spelling of each item very very carefully.
2. the CSS may be working but the effects may not be visible! set a bright background color.
3. use z-index to ensure that the content is not behind some other element.
4. when doing a web search use "syntax" as one of the search terms.
5. dont forget to use the forums- Daniweb is one of the best :)
Someone may know of a list, but I couldn't find it.