CEED

Do, absolutely, go for it. It is much better than going for an MBA (unless the MBA serves a grand plan of yours). With an M.Des in hand, sooner or later you'll find yourself wanted badly by the industry. The Indian manufacturing/services mindset is changing, and we are moving towards more of a 'build a brand' mindset. The things that'd get us there are:
a) Greatly designed products and services
b) Great marketing
A design course would not just give you the skills that the industry needs, but also a way of thinking that unlocks doors.
I personally have not gone for a Master's degree after Bachelors in engineering, but being in touch with designers has made me hold them in high respect.
For entrepreneurs:
Design thinking makes you see opportunities, and that's great for an entrepreneurial mind.
For professionals:
The pay may be low (though that's changing too), but some of the projects you might be on will have a potentially great impact.
That said, it's really hard work being a designer if you're up for it and for a prolonged period of struggle, a world of wonder awaits you.

Hello,
No, you cannot take CEED just after class 12th. The eligibility criteria for CEED exam is:
There is no bar to either the age of the candidate or the number of times a candidate can participate. The minimum academic qualification for appearing in the examination is a Bachelor's degree in Design, Architecture, Fine Arts or Engineering from a recognized college or university of India.
All qualified candidates with a valid CEED examination score become eligible to apply for admission to various design programs under IITs and IISc. A valid CEED score does not, however, promise admission to the desired institute. Candidates are always required to appear for a second test known as the Design Aptitude Test followed by an interview prior to final selection by the respective institutes.

It's a really tough question. I really had to struggle a lot with this myself. But I'll try to answer to the best of my abilities.
I am guessing that you're going to take CEED this year so that'll be CEED 2014. It will take place in the November end (mostly).
The first thing you need to understand is that anybody with an open mind and decent drawing skills can get through CEED. You don't need to be extraordinary at drawing (obviously it does help if you are extremely good at it).
Question Paper format:
Total 100 Marks. The paper has 2 parts.
Part A- Multiple choice questions-50 Marks. It will test you on many things from General Aptitude, GK to Analytical ability. Famous architectures around the world-Bridges, buildings, etc.
In CEED-2013, I got a few questions on mechanical pulleys (physics) so there will always be surprises.
Part-B: Again divided into 2 sections. Drawing Ability and Design Problem Solving. Total 50 Marks. The 2 most time consuming things in the entire paper.
Also, the paper format may change, but you will be notified on the official CEED website if that's the case.
Stuff you need to know before appearing for the exam:
You need to start preparing right away. Read anything you can find on interaction design and visual communication. Go as deep as you can into that subject.
Check out:
Smashing Magazine for professional web designers and developers
Complete Beginner's Guide to Interaction Design-UX Booth.
Another great resource-Teacup Blog
Previous Question Papers-Common Entrance Examination for Design. Go through the previous question papers and try to answer as many of the questions as you can. Trust me you will learn a lot of things by answering them.
You need decent drawing skills. By the time you take the exam, you should be able to draw fruits, vegetables and everyday objects from your mind as far as possible in 3D perspective.
Check out how to draw stuff, step by step, pop culture, with our free online drawing tutorials.
Industrial Design Sketching and Drawing Video Tutorials
Be creative while answering the questions. What I mean to say is try to use the answer sheet to your advantage and present your points clearly and accurately. Try to think of different ways you could use the answer sheet to present your answers. This is not really that important. But it's one of those good-to-know things.

CEED is conducted by IDC, IIT Bombay in order to offer admission to aspirants in M.Des programs offered at colleges accepting CEED scores for admission. Self-preparation is an ideal way to prepare for the NIFT exam. The exam includes two parts A&B.
Part A consists of visualization and spatial ability, environmental and social awareness, analytical and logical reasoning, etc.
PART B consists of drawing, creativity, communication skills.
You can check the detailed syllabus on:
https://www.shiksha.com/design/exams/ceed/syllabus
However, the revision of the sample papers will help you develop a better understanding of the possible type of questions and also the approach to be used to ace the examination.
Please refer to the link for some papers: https://www.shiksha.com/design/industrial-product-design/articles/ceed-previous-years-question-papers-2010-2016-blogId-13224