For best results increase gain untill interferece can be seen on the screen then tune back slowly untill it dissapears. Match your display scrolling speed to the speed of your boat, the faster you travel the faster your sreen update. Do you have tvg as a setting as this can be tweaked as well. For bottom fishing use bottom lock or zoom to expand the sea floor features and give you the most detail of fish that may be present. Its best not to travel too quickly as it is possible to miss critical features. Pay attention to color of objects displayed . The darker the colour the higher the density of your target and most likely the size of your target If you have a transom mount transducer clean the bottom side on a regular basis as grime and dirt can build up. Be aware of bottom type and structure. Habitat and knowlege of fish specie habits are most important. RE tune your sounder for different depths. Know the habits of each target species as the best tech is only the start of your adventure. For the best learning experience get a copy of the J Adams book How to use an echo sounder. It has a life time of experience and even an experienced operator can learn a lot. Have a look at u tube videos on how to use your sounder there are many useful clips.