When you do something conscientiously, you do it with real care because it is your job or your duty — the whole job, not only the easy or visible bits. A student who works conscientiously checks the dull parts too; a nurse who does the work conscientiously does not skip a step just because nobody is watching. It is a slightly formal, praising word. Teachers and bosses like it; friends in a chat rarely type it. People sometimes stretch it to mean only “very carefully, leaving nothing out,” even when duty is not really the point — though actually a little smell of duty usually stays. It is not the same as consciously, which is about noticing what you are doing, not about being thorough and responsible.