This is what you want to do
to your body / muscles every workout, shock the body into growing!
This is done by switching up
your workout, doing different exercises that you're body is not used to
and using advanced techniques such as
stripping sets and
supersets
Switching up you're weight
lifting program is a good idea, switch it when you're body is no longer
soar by the next couple of days after a workout. If you need ideas use
the weight
lifting program page for help.
If my muscles are not soar by
the second day after a workout I consider it that my muscles have not
been shocked by my workout. It can be for a number of reasons, training
intensity was not there and / or my body is getting used to my weight
lifting program.