Most bricks happen either by not knowing what you're doing, or following outdated guides. My advice is to keep things calm, read carefully, learn about how the wii and the exploits work and get familiar with the terms before actually doing something with your console. The sticky isn't stickied without reason. The link to the complete softmod guide is an important one. And when you finally decide to actually do something...there is modmii to help you.
I also strongly second Category's tip. bootmii is similar to a backup program for windows, so there is no reason NOT to get it. And if you have a red wii, you'll need to install priiloader as well before doing anything fancy (bootmii will make the backup...but in case things DO get out of hand, you'll need a way to access it).