My #1 top tip is to make a backup of the original recording before doing anything else.
snskid909 wrote:6. Noise Removal
Yes it works. No its not magic.
The main thing to take care about with Noise Removal is not to overdo it.
If there is a lot of noise (and there usually is from camcorder recordings) it will almost certainly not be possible to remove all of the noise without also causing significant damage to the sound that you want to keep. Attempting to remove too much noise will often produce a metallic bubbly
effect to the sound. Achieving best results is a balance between achieving acceptable noise reduction while not damaging the remaining audio too much. It is often useful to try out the Noise Removal settings on a few short selections of the audio (Ctrl+Z to undo the effect). When you have found settings that you are happy with, apply the effect to the entire track.
More information about Noise Removal in the manual: http://manual.audacityteam.org/man/Noise_Removal
Noise Removal should be performed before
using any compression type effects as these can cause the noise level to fluctuate, making Noise Removal far less effective.
Camcorder recordings often have a lot of low frequency noise (hums and thumps) and no useful audio in the very low frequency range. Applying a low bass-cut filter to the track before any other processing can often make a significant improvement to the sound and help other effects to work better. I generally prefer to use the Equalization effect for this.