Even if standards are set up browser don’t use the same standards style. For example the margin-bottom on a paragraph in IE hasn’t the same amount of pixel than in Firefox.

So to start on a fresh base we use CSS reset. Take off evrything and rebuild all the style you need. A comon technique is using the * selector:
*
{
margin:0;
padding:0;
}
This is very simple and reset pretty much everything that is set up originaly in the browser. Now if you want to get a more efficient and selective reset theire is some out there that can help you.

The one I personaly use, and I think is the most famous CSS reset, is developed by Eric Meyer: http://meyerweb.com/…/reset-reloaded/.

This is a radical reset. Provides a fresh base to start, but takes off to much in my opinion so here is my version of CSS reset from Eric’s:

/* CSS Reset by Eric Meyer */
html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, dl, dt, dd, ol, ul, li, form, label, table, caption, tbody, tfoot, thead, tr, th, td
{
margin: 0;
padding: 0;
border: 0;
outline: 0;
font-weight: inherit;
font-style: inherit;
font-size: 100%;
font-family: inherit;
vertical-align: baseline;
}
/* remember to define focus styles! */
:focus
{
outline: 0;
}
html
{
overflow-y: scroll;
}
body
{
line-height: 1;
color: black;
background: white;
}
ol, ul
{
list-style: none;
}
a img,:link img,:visited img
{
border: 0;
}
/* tables still need 'cellspacing="0"' in the markup */
table
{
border-collapse: collapse;
border-spacing: 0;
}
caption, th, td
{
text-align: left;
font-weight: normal;
}
/* End of Reset */

Pretty much the same except that I have taken Fieldset and Legend off the main reset because I like the original style of them. I have also added the trick to manage the scroll bar (See Avoid scroll bar moving effect for more details). I have taken off the part on blockquote as I try to stay away from using CSS to add content to my page, doesn’t seems right to me.