For the most part yeah....You might want to train you pick hand to be a little more minimal & controlled in it's movements....Mainly based on the type of music that you are playing, of course. ;)
If you're looking to emulate the Pete Townsend windmill type of motion or something, hitting the body of the guitar might be unavoidable.
But for most of your average picking/strumming techniques...striking the body hard enough to be audible is probably not something that you will want to continue.
You might just try to start off by easing up on the force you apply with your picking/strumming stroke....if striking the body of the guitar is something that you really having trouble controlling...my first thought, is that you are either striking the strings way too hard or are way too tense in you motion.
If you are strumming...maybe start off by relaxing your hand & grip on the pick and dragging the pick across the strings with just enough force to sound the notes clearly. Focus on controlling the motion of you picking hand, by keep the motions efficient and minimal, so that your hand is striking the strings in a controlled manner & not flailing off course and striking the body. Work your way up slowly through quicker tempos & higher volume until you can play pretty much as hard and/or as fast as you want, but still be in total control of all your motions.
For alternate picking/economy picking....It would be much the same sort of deal, but you would be going through the motions string by string instead of strumming chords & stuff.
That would be my relatively short answer...for more detailed tech tips, I would go through some of the beginner oriented material here, that focuses on building your basic picking/strumming techniques.
Don
