Three things you need to know about muscular training.
Always use different techniques, doing the same work out will prevent fewer gains and could lead to burning out your muscles. By changing your exercise routine you will be able to keep on top of you're training by using different muscle groups. Failing to impose any new techniques such as increasing number of reps preformed or weight increase will simply lead to keeping them the same size. The only benefit will you will have will be increasing cardio fitness in your muscles, the down side will be no growth benefits.
Stretching is important to speed up the recovery and increasing the muscles range of motion, making more room for muscular growth. You are able to benefit on visual toning of your body, when stretching we unlock more muscular fibres therefore build more muscle. You should always use flexibility training in a normal program as it will prevent injury to muscular body tissue.
Always drink protein shakes an hour post exercise, protein-carb mixture after training starts the recovery process immediately, replenishing lost glycogen stores and helps by providing the nutrients your body needs to repair muscle tissue. Skipping a shake post workout and waiting for your next protein fix an hour or more after training is no good, have your shake ready and feed your muscles.