The first key to building bigger stronger muscles is progression. Weight training should be more correctly called Progressive Weight Training. 

The  second key is using the most effective weight training equipment in the world.  It is not a machine, it is not free weights, nor is it a rubber band, a trendy kettle bell or a big fat truck tire.

 What Is The Most Effective Training Equipment In The World
 Answer=A note book and pen.
 
A bodybuilding journal/log is the key to ever-increasing progressive overload and is the most important bodybuilding equipment you will ever work with.
Get a training log, Start using it!
A short pencil is better than a long memory!

Stay Strong Lift Heavy

John