Both words have to do with the mind, but it's more important to be conscious, or awake, than conscience, or aware of right and wrong. Remain conscious while listening to your friend's moral dilemma so you can use your conscience to give good advice.

Conscious, pronounced "KAHN-shuhs," means being aware of yourself or the world around you. It also means being sensitive to something or being awake, not asleep or insensible:

Witnesses say he was bleeding profusely but conscious and talking. (Washington Post)

He was even horribly conscious of a slow pallor creeping over his face. (Bertram Mitford)

Conscience, pronounced "KAHN-shuhns," is a moral understanding, an inner feeling, of right and wrong. If you were a cartoon, your conscience would be that little angel on your shoulder, telling you the right thing to do (and to ignore the little devil on the other side). See the word in action:

They went out guiltily, as men whose consciences troubled them. (Richard Marsh)

Passports are not required, but a social conscience probably is. (New York Times)

To help keep conscious and conscience straight, try emphasizing the second n in conscience, remembering that the conscience deals with your inner thoughts.