There is a time and a place for passive voice. The habit though is to use it *constantly*, and that's pretty much the worst thing you can do. Passive is good for exposition, which, again, is something you should try to avoid -- but when it's required, direct sentences can be counterproductive. It should generally be treated as seasoning, and not as an ingredient. Active voice needs to be the bulk of what you write; until you're fully confident in your active voice, don't screw around with passive very much. 

Example of ALL PASSIVE ALL THE TIME

Pizarro was a conquistador. He was spanish. The Incas were conquered by him in the 1500s. It was crazy.

Example of ALL ACTIVE ALL THE TIME

Pizzaro became a conquistador. A spanish family raised him. He conquered the Incas in the 1500s. Pizarro epitomized craziness.

Example of A HEALTHY BALANCE

Pizarro was a Spanish conquistador who conquered the Incas in the 1500s. It was crazy.