First, It would be good to have bit more information. The question is also too general. If your site is live give us a link, it may help some. Also describe the variations your are seeing and then post the code that is relative to the problem.
All browsers handle HTML, CSS, and javascript differently. None of the browsers are 100% compliant with the W3C standards but most are very close. IE is the worst of them so you want to write your HTML, CSS, and javascript for mozilla and test in it, and then use some features IE has built in to fix any errors IE has.
Their is a few general things you can do to make things a bit more uniform between browsers. First, I would note is to use the <!DOCTYPE> declaration in HTML to force a more standard compliant display of HTML. DOCTYPE Declaration
Second you can use the conditional commenting for CSS in IE. IE Conditional Comments
<!--[if IE]>
<style>
#someid {
height: 200px;
}
</style>
<![endif]-->
Those are some the basics things you can use if you are not already. After that if you need help thoroughly explain the exact problem and include the relevant code in your post. Doing this will improve your chance someone will reply and reply with an answer that will work.
