Not seeing all changes on editing through skinning and CSS

I am very new to wordpress and am not web savvy yet, and after hours of searching forums and reading tutorials I really need some help..

I have a very basic template but I have been looking to change 3 things. It’s easier for me to do so via skinning but whenever I make changes, not all of them appear, for example I want to change the colour of the text in the navigation bar but it doesn’t work, but changing the background bar does?!

When I try to copy a code I’ve found in the forums into the CSS editor, it also doesn’t work, (except just one code changing the post title to the center) not however when I want to change the colour and size of that same title.

I was looking for ages to adjust the sub header in the top left with font and size, but nothing is happening either. I still can’t work out what I’m doing wrong? I’m copying and pasting codes and then back-tracking.

So I’m a little unsure why some things are working and others not?

Any advice would be really appreciated!

Thanks!

http://evolveandexpress.com/