Data Entry is one of the best part time job after class 12th. It requires a little or no expertise and also it is easy to get a job in this.

Also you can try freelancer.com (//freelancer.com) to get small jobs  which can help you to earn money.

Even you can try into a customer associate job, where you will have to call or chat with the customers regarding their issues. This is provided by Amazon and is paid relatively better than others.