A simile is a comparison between two items using the words "like" or "as". Her eyes were as blue as the sky and like huge, round sapphires when she smiled.
Personification is giving human qualities to any inanimate object. Basically, it's making the object like a "person". The wind whispered his name and tortured her with his memory. Wind is not a living entity, so it can not whisper or torture.
Mood is the feeling of the atmosphere in the story. This can be achieved with lots of different things...stormy weather and wind, rain, thunder, lightening gives an ominous or threatening and angry mood. Mood can be tense, happy, anxious, angry, frightened...basically any emotion humans can feel can be conveyed through description, language, and interactions with characters. Sounds devices can also be used to achieve mood. An angry person may use words that contain many hard consonant sounds which will give it a more clipped, hurried, and angry feeling. Take this example from the Red Badge of Courage:
Besides, a faith in himself had secretly blossomed. There was a little flower of confidence growing within him. He was now a man of experience. He had been out among the dragons, he said, and he assured himself that they were not so hideous as he had imagined them. Also, they were inaccurate; they did not sting with precision. A stout heart often defied, and defying, escaped.