Always use the ACTIVE voice unless the passive voice is more appropriate (for the purpose of tact and diplomacy).
Here are some examples of sentences written in passive voice that have been rewritten in active voice*:
Passive: Sections A and B should be checked for errors.
Active: Check sections A and B for errors.
Passive: Hurrying to complete the work, the cables were connected improperly.
Active: Hurrying to complete the work, the technician connected the cables improperly.
Passive: It was reported by the testing facility that the new model is defective.
Active: The testing facility reported that the new model is defective.
*sample sentences taken from Handbook of Technical Writing, page 564.