I knew someone would ask that! The sad fact is that Powerpoint isn't really designed for this sort of presentation so it's a bit laborious to change each slide to have a different background. Not impossible, just a bit of tedium. Let me show you.

First off, I start out with a plain slide with no master template. It's easy to push all the text on all the slides to a single typeface (how? go into Normal View, then click and drag to select all the text on all the slides, then chose a new font!) and the default layout is usually fine for my text slides - most of which end up being Title Slides, by the way, not Bulleted List Slides - so here's what I'd typically be looking at:

Now, simply right-click (or, if you're on a Mac like I am, Control-click) and you'll see the following menu:

The option you want is highlighted: Slide Background.... Select that and here's what you'll see:

Almost done. Click on the pop-up menu and it'll show you the set of colors in the current color "scheme", but below it you can specify a new color from a color picker:

Choose "More Colors..." and you'll finally have the color picker:

Choose the color you want, then click the necessary "OK", "Apply" and "Save" buttons to get back to your master slide, make a few tweaks on the font color and size, and suddenly your slide is looking at lot more memorable:

Hope that helps you see how to create more visually interesting slides in Powerpoint.