I am a student of Computer Science. It would be great if i could do some jobs in the internet and make some money. So is there any tips for me to do so ?
Create an online presence (example: Facebook Page, Website, Behance Profile, etc. to showcase your work)
Start by serving people you know how to design requirements and ask them to leave testimonials for your service.
Use Social Media and other avenues to spread your freelancer profile/portfolio, and land jobs/clients. Don't worry about your age, don't mention it if you don't have to. It's your skills that matter. Showcase your work as best you can.
TIP: I suggest starting off with a discounted price but good service quality. Remember to keep communication going on while doing your projects to keep clients engaged to you.
You don't have to register a company legally yet. This is how you start. Clients can transfer money your bank account or Paypal, etc.
Hope this helps.