1. Google’s Page Speed Online ( https://developers.google.com/pagespeed/) is your quickest way to evaluate the time it takes to complete a page is to go to and enter in the URL of the page in question. Try it on your main domain name for a first impression. This will give a score for your page, based on “best practices”, which are known and established ways of speeding up load time.
2. Firebug (http://getfirebug.com/) is an “addon” for the Firefox web browser. As a serious web developer, you must have Firefox — with Firebug — on your machine. It will help you optimize your pages. If there’s slowness from your back-end services, Firebug gives you a timeline of each downloaded element of the page, so you can start making intelligent guesses (or experiments) to determine what back-end part of your system might be slowing down the page.
3. YSlow (http://developer.yahoo.com/yslow/) is an addon for Firefox as well, and there is a YSlow web application for Google’s Chrome browser. It also grades your page according to best practice requirements.
Best-practices have been succinctly encapsulated in “HTML5 BoilerPlate”. Even if you’re not designing for HTML5, it’s the best code base with which to start. Paul Irish lives on the A-List of web development best practices and he gives a YouTube presentation of his work at http://www.youtube.com/watch?feature=player_detailpage&v=qyM37XKkmKQ.