You just created a new web site but want to pass on the search engine rankings of the old one to the new one. What is the most effective and spider/visitor friendly strategy to implement your web site redirection? You should use a 301 redirect. 

Always use 301 (search engine friendly redirection) 

What is a 301 redirect?

It is used when you want to redirect your web site or web pages. The code “301″ is interpreted as “moved permanently”. 

Requirements for using a 301 redirect

• .htaccess file

How do I implement a 301 redirect?
 

For example non www to www

<IfModule mod_rewrite.c>

RewriteEngine On

RewriteBase /

RewriteCond %{HTTP_HOST} ^example.com [NC]

RewriteRule ^(.*) http://www.example.com/$1 [R=301,L]

</IfModule> 

Save the .htaccess file to your root directory

 When the search engine spiders visit your old web site or web pages, they will automatically be redirected to the new web site or web page.