Both words have to do with the mind, but if you are conscious, you are awake, and if you have a conscience, you are 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:
Polaski said the worker was conscious and alert when police arrived. (Washington Times)He was even horribly conscious of a slow pallor creeping over his face. (Bertram Mitford)
“I don’t have any shoes,” I told Lissa, suddenly conscious of my bare feet. (The Old Willis Place)
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)
Jaime would have liked to do something for them, but his conscience told him it was better to spend his extra money buying food for the hungry than luxuries for his sister and his niece. (The House of the Spirits: A Novel)
To help keep conscious and conscience straight, try emphasizing the second n in conscience, remembering that the conscience deals with your inner thoughts.