You may want to check out the following article:
The section Sample HTTP Exchange could help you getting started. Quoting:
The server should respond with something like the following, sent back through the same socket:
HTTP/1.0 200 OK
Date: Fri, 31 Dec 1999 23:59:59 GMT
Content-Type: text/html
Content-Length: 1354
<html>
<body>
<h1>Happy New Millennium!</h1>
(more file contents)
.
.
.
</body>
</html>
After sending the response, the server closes the socket.
The full protocol is defined in RFC 2616 if you want to get serious about this.