Customize your Magento with local.xml

./app/design/frontend/default/default/layout/local.xml
 
<!-- disable footer links -->
<remove name="footer_links"/>
 
<?xml version="1.0" encoding="UTF-8"?>
<layout>
<default>
	<!-- Remove callouts and raely used stuff -->
	<!-- <remove name="right.poll"/> -->
	<remove name="right.permanent.callout"/> <!-- romove back to scholl banner in right panel -->
	<remove name="catalog.compare.sidebar"/> <!-- romove compare block in right panel -->
	<!-- <remove name="left.permanent.callout"/> -->
 
	<!-- add the local stylesheet -->
	<reference name="head">
		<action method="addCss"><stylesheet>css/mr.css</stylesheet></action>
	</reference>
</default>
 
<!-- 4 column per row -->
	<catalog_category_default>
		<reference name="product_list">
			<action method="setColumnCount"><columns>4</columns></action>
		</reference>
	</catalog_category_default>
 
	<catalog_category_view>
		<reference name="product_list">
			<action method="setColumnCount"><columns>4</columns></action>
		</reference>
	</catalog_category_view>
 
	<catalog_category_layered>
		<reference name="product_list">
			<action method="setColumnCount"><columns>4</columns></action>
		</reference>
	</catalog_category_layered>
 
</layout>
 
# Links
http://classyllama.com/development/magento-development/the-better-way-to-modify-magento-layout/