The same topics as in any other language. This italki site will help you http://www.italki.com/learn-chinese/en-us

most Chinese on initiatl stage will starta conversation with introduction of yourself. for example, hello 你好，where you come from?你从哪里来（你是哪国人）？what is your name? 你叫什么名字？ where is your hometown？(你家乡哪里？）what is your hobby? (你的兴趣爱好是什么？）

Hi, I am Allie, a Chinese teacher from MeetMandarin. Hope the following phrases could help you. Nǐ hǎo! 你好！ Hello! Nǐ hǎo mɑ? 你好吗？ How are you? Nín ɡuì xìnɡ? 您贵姓？ (“贵ɡuì” means honorable here ) What’s your honorable last name? Nǐ jiào shénme mínɡzi? 你叫什么名字？ What’s your name? Nǐ duō dà le? 你多大了？ How old are you? Nǐ shì nǎ ɡuó rén? 你是哪国人？ What’s your nationality? If you want to learn more phrases and sentences about starting a Chinese conversation, you can visit this article: http://www.meetmandarin.com/articles/how-to-start-a-conversation-in-chinese.html

你好吗？ ni hao ma ? How are you ? 你叫什么名字吗？ni jiao shenme mingzi ma ? What is your name? 认识你很高兴 renshi ni hen gaoxing nice to meet you 我是。。。wo shi ... I am .....( your nationality) 我在。。。住 wo zai .....zhu I live in ...... ( your country of residence) 你的爱好是什么？nide aihao shi shenme? What are your hobbies? 你做什么工作？ni zuo shenme gongzuo? What do you work?