fundamentals before you know when you can break the rules.
You have to know what flavors work together and against each other
before you cook a feast fit for a king. You have to learn grammar and
spelling before you can write a book that others will actually enjoy.
Just the same way you have to learn how to create squares and boxes in
catia/solidworks before you create a gas turbine engine in it. You
have to create a simple truss in ansys, before you can mesh and
analyze the fuselage of an aircraft.
Fundamentals are must and this is where you should spend maximum of
your initial time. Even if you consider yourself as an expert, devote
30 mins daily on exploring the fundamentals.