Here’s an article by Amy Roberts, CPT on How to Build Muscle. For the article, she asked fitness and nutrition professionals across the country about sample workouts, theory, and nutrition recommendations.
As someone who lifts for strength:mass ratio and overall athleticism primarily, my goal is not necessarily to put on as much muscle as possible for the sake of it, but many people who lift want this. It is important to have a program that fits your personal goals for fitness and physique. It is very possible to be training incorrectly for your goals. This article is a good place to have ideas on how to train.