Understanding how to incorporate harass as part of an economical buildup towards a solid lategame army is vital. I personally learnt how to be a good player at starcraft by watching a lot of GSL and listening closely to Artosis comments about how the builds operate. He is a wise man. There are many other great casters (Day9) and coaches (mrbitter) who give similarly fantastic advice though.
Essentially you must strive to become a solid macro player to improve at the game. Getting active on forums and discussing/reading discussions on strategy and builds is vital. Training specific builds to perfection is also important. Watching and learning from VoDs is also a simple and easy way to improve .
Overall you have to look at the game not with awe, but with a critical and discerning eye.
Even the smallest donations help keep sc2sea running! All donations go towards helping our site run including our monthly server hosting fees and sc2sea sponsored community tournaments we host. Find out more here.