How to make a website W3c compatible?

Issue

• The following errors are seen while trying to make a site W3c compatible :

Warning Character Encoding Override in effect!
Validation Output: 4 Errors

Error Line 13, Column 45: Bad value pragma for attribute http-equiv on element meta.
<meta http-equiv="pragma" content="no-cache">

Error Line 14, Column 7: Element head is missing a required instance of child element title.
</head>

Error Line 15, Column 54: script element between head and body.
<script language="JavaScript" type="text/JavaScript" > 

Error Line 15, Column 54: Cannot recover after last error. Any further errors will be ignored.
<script language="JavaScript" type="text/JavaScript" > 

• How to make a site w3c compatible?