There are actually a lot of us here who are knowledgeable about this stuff.
However, we all like to do things in our own way. As long as you stick to the specifications, and can validate it and pass, then it doesn't really matter how you do it. You'll eventually learn your own way of doing it and stick to that.
As for the differences between IE and Firefox, just do trial-and-error. You'll be able to tell what doesn't align up or what doesn't look right. Use that information to Google for fixes or workarounds, or just start tweaking values yourself. You'll want to start off with a duplicate CSS of your Firefox CSS file and start modifying it from there.
Dealing with the differences between IE and the rest of the browsers can be quite a pain. Have fun.
Feel free to give links or ask any specific questions here. We can't answer such broad questions too well.