The best advice I can give you is to study the following "Cascading Style Sheets, level 2 revision 1
CSS 2.1 Specification
" guide from w3.org. It is in PDF format.
Trust me. It worths every second you invest on it.
That way you will understand firsthand, how CSS works, why you see differnces between browsers and how you can overcome them.
Perhaps, it is not the easy answer you were expecting, but it is better to learn how to fish, than expecting from others to feed you.