In particular, make sure there is no background noise. Low-frequency noises, like the hum of a ventilation system, will be an inseparable part of your audio track, and no amount of tweaking will eliminate it altogether. Also, the downsampling and compression you will have to perform in order to make your audio Web deliverable will only emphasize any flaws in your recording. Once you have digitized your audio, spend some time processing it. If you have ever scanned slides or photos you will have discovered that the simple process of scanning yields an image that is inferior to the original.
Scanned images require sharpening and contrast corrections.
In the same way, audio that has been digitized requires normalizing. This ensures that you are working with the loudest possible audio signal. This is even more important when dealing with Web audio because the downsampling required for the Web will mean that you will lose volume. A very effective and manageable method for using multimedia on the Web is to synchronize good-quality audio with still images to create a slide show. Using this approach you can communicate concepts by providing the information via audio and using the still images to add visual emphasis.