Lesson 1: Anti-Aliasing and what the hell is it?
Anti-Aliasing is a tough-guy word that artsy types use to say "is it smoothed or not"? That's all there is to it. Don't forget that your graphics package probably came with a help file, so look up how to Anti-Alias. It'll be in there, it's usually a checkbox or a button of some type. Leave it on, ALWAYS. Unless you are trying to do something artsy and very blocky, not using it makes you look like a tool.

The S on the left is antialiased. See how it looks smooth? That's antialiasing. Antialiasing is smoothing. Say it again. Don't forget it. See how the right S looks kinda blocky? That one is not antialiased. Get it? Got it? Okay. Now even moreso, here's why you really care.

Take a look at this picture

That's why I'm the king around here. Because I can make circles like that. Anyway, these circles are antialiased for a black background. And they look darling, don't they? Now take a look at this picture:

see how it looks like crap? that's because the circles on the top were antialiased for a black background. The circles on the bottom were antialiased for a white background. Look at the difference here up close:

Notice how the graphic on the left has the red, then it has deeper shades of red that blend it into the background? Well, that's the magic of antialiasing. The one on the right was also antialiased, but for the background of white. You can see how it goes from red, to less red, to pink, to light pink, to white. Now this looks incredibly crappy on a black background. This is the effect that you see in lots and lots of places.

So what is the moral of the story? Well, this is simply lesson one, it's a very basic lesson, but mistakes that a ton of people make. When you are making graphics, make sure that you have your antialiasing on, and make sure that when you combine all of your layers or objects, that you do it with the color that you are going to be using for your background. If you are using a patterned background, just make sure that the color is close. Hopefully you're not using a high contrast background, because no matter what you do your page will look like crap. Make sure your background is clean, not too high in contrast (see TDFv3, appearances), and keep the antialiasing on, and to the right background color. Your images will look smooth, clean, and your site will look a little more professional.

Beautiful language, isn't it Marge?

Next Lesson: How to avoid that monstrosity above!