Find a good piece of structure and mark it well with buoys...

Then scan it from several different directions using different settings each pass...

Scanning the same structure over and over eliminates the "Enviromental" variables (water changes, depth changes, bottom composition changes)...and gives a better understanding of what unit settings affect the image in certain ways...

Take notes of what each settings change does to the image...

I still use this same testing procedure as much today as when I first bought my unit...(especially when testing some of my experimental xducer setups)...

Rickie