I've been using JavaScript since I don't know when. I've done a lot of pretty neat stuff with it but my approach has mostly been as follows:
I've now realized that something's darn wrong with my approach regarding JavaScript! I've used up many could-have-been-fruitful years doing JavaScript stuff with only what I already know. I should have gotten to know the intricacies of JavaScript better and explore what all is there.
With the advent of AJAX and Web Services, I've started taking a closer look at JavaScript.
I've started by learning how to make better use of JavaScript's OOP features.
Here's a good link to get started: http://devedge-temp.mozilla.org/viewsource/2001/oop-javascript
Also here is some very basic info that says that everything in JavaScript is an object and every object in JavaScript is actually a hashtable!
For a more complete coverage of JavaScript, check this out: http://www.crockford.com/javascript/survey.html