I am a plant killer

My friend Christina came over last night for dinner & to watch The OC with me. She brought me a plant. It's a little plant with pink roses on it. I have never been able to successfully raise a plant. I always kill them. Usually about 2 weeks after I get them. I would really like to do well with this one! I read the little tag that came with the plant, so I know I need to leave it in the sunlight (it's on a window ledge) and keep the soil moist. Any other suggestions?