If you are building a website you need to start off with a clean slate and to do that you need a CSS reset. it is a small stylesheet that removes most, if not all of the browsers’ default styles. It eliminates many of the inconsistencies between the different browsers and truly lets you start from the bottom.
There are a lot of CSS resets available, just about every CSS framework comes with one (more on those and why I don’t like them in another post). I always use Eric Meyer’s Reset CSS. Just copy and paste or @import it into your existing stylesheet and get to work.
Most of the projects I work on at my job do not make use of a style reset, so I am constantly switching between browsers and wrestling to get things to look as close to the same as possible. When I start new projects, I start with a reset and I almost never have to worry about browser quirks. Of course there are still some issues, but they are usually fewer and easier fixes when you start with the reset.
If you aren’t already, you must start using one. For something so quick to implement it really does save you a lot of time down the road.