Here a a couple of my favorite settings for effective tone. The first setting will be for a clean sound used for rhythm guitar. The second will be for a dirty lead sound.

You can copy these sounds if you want, but you'll be far more satisfied to come up with your own. Use these sounds and tweak the individual controls to see how they each effect the tone. If nothing else, give 'em a try just to see if you like or hate them.

Make a special note that these settings won't necessarily work on a tube amplifier. Amplifiers are like guitars in that they each have their own unique sound. Don't be fooled into thinking one size fits all.

Good luck!