It's midday, and I find myself looking at a few hundred lines of code, the product of a few hours work. I know because of the scope of this project, and how much more lies ahead, there's going to be a lot of need for optimizing what I'm creating. I find myself constantly tweaking it here and there, not only trying to make it more clean and readable, but smaller and more efficient.

I write a lot of JavaScript, mostly within jQuery or Prototype, and making things work efficiently is pretty important. I don't have a routine for testing how efficient my work is, but I do usually have a good feeling for what is working and what isn't.

Does anyone have any tips for how to write efficient code, or want to share experiences that have been helpful to you in this area? I'm interested in hearing about any platform or language.

I'd say a few things:

• Be careful not to optimize too early on. I'd get it working first and then profile it to see where it's bogging down. For JavaScript, Firebug is great for that. Once you see where the bottlenecks are, then you can work on those parts, but it save you from working on things that aren't a problem.
• Separate your code so that each function or method does only one thing. It's more maintainable and you'll find it easier to optimize when you need to do so.
• Especially when working with JavaScript, use GZip compression. You can do it through Apache or you can use a script to enable it. You can get around 70% savings on download size with GZip.
• Leave your comments, etc. in the code and use a script to concatenate your JavaScript files into one or two files and then minify them.
• If you've never checked it out, I'd highly recommend MooTools. They have a class based system and the plugins I've seen for MooTools generally tend to have a higher quality of code because of it over some of the other libraries.