Taking a tack sharp photograph...

Here are a few resources that provide the information that you need to know (and do) to make sure your images are sharp.

First, it's the Digital Photography School with "How to Take Tack Sharp Images". This articles has eleven tips and techniques including how to hold your camera correctly. I know it sounds simple and (painfully) obvious, but do you hold your camera because you were taught how to hold it or because it's habit and comfortable? I was taking pictures for some time before I came upon a tutorial on how to hold a camera (and breathing technique). I realized I had been stepping up to the plate but no one showed me how to handle a bat.

Second, we have WonderfulPhotos.com with thirty three tips and tricks. As you can imagine with that number of tips they cover a bunch of things, right down to have your lens calibrated.

Third, pixiq has "8 Steps to Sharper Photos" and in one of this steps they explain why shooting RAW will help you get the sharpest possible image. They have a ton of tips, tricks, and techniques that you will want to check out.

Lastly, Mansurovs Photography has put together "How to Take Sharp Photos" that has lots of tips, sample images, and corresponding links, so be sure to check it out.