Hi

Relax and consolidate your self and prepare your own plan on how you want to go about it. Check my lessons learned posts http://mypmpll.blogspot.in/

>>What should contain in the Brain Dump ?

Prepare a cheatsheet of all areas, terms, concepts which you feel less confident about. Revisit those few times and try to imbibe it. Jot it down on scratch paper in 1st 15min.

>> What should I carry for the exam ?

You are not allowed to carry anything except the identy card. 

>> What are the must do things I should revise before the exam ?

Revisit ITTO's throughly

Formulae

Quickly browse through the Knowledge Areas

>>Is it worth revising the entire text book  Head fist and PMBOK once again  or should I focus on more test ?

Probably an exam would be good idea and review the questions you got wrong

>>Any tips on how to focus the 200Q with full attention to detail ?

Plan the exam

Divide the exam in 4 milestones i.e. 50 questions / hour

Take a small break (15-30sec) after each milestone, take a long breath. 

Notedown questions to be reviewed on the scratch paper

Do not go by just a gut feeling. Think logically for every single question you confident about as well as not confident about.

Before clicking on next, ensure you have selected a right choice. 

What should contain in the Brain Dump ?

The best thing to contain in the Brain Dump should be the page 43 - Project Management process groups and knowledge area mapping, and the formulas. By now you should have already memorized it and are able to write them on a paper with a pencil in 10 minutes or less.

If you have difficulty remembering certain things add them as well to this list.

What should I carry for the exam ?

Just your photo id card and/or whatever id your center requires you to carry. You are also allowed to carry water and food which you can keep it outside the center near the reception and when you take a break you can have it. Other than this you don't need to carry anything

What are the must do things I should revise before the exam ?

My advice is to review Rajesh Nair's notes but if you feel they are too many things to revise then stick to ITTO

Is it worth revising the entire text book  Head fist and PMBOK once again  or should I focus on more test ?

A quick glance of PMBOK should be enough. I don't recommend going through any other test. If you have time then go through in detail the sections where you scored lesser 

Any tips on how to focus the 200Q with full attention to detail ?

Plan your break either after each 50 questions or each 100 questions. Your target should be to complete 50 questions every 50 minutes so that you have 40 minutes left in the end for review and breaks if you want. Main strategy should be not to spend too much time on a question which you are unable to answer. Just go with the mind set that there will be questions you will not understand and/or questions that you don't know answers to. Make sure that you mark the ones that you are not sure about and then review them at the end.

Best of Luck.