Final weeks: calculation/silly errors and speed :!:

First ensure that you understand the concepts very well by going through books/posts (whatever you need). See some examples of how people solve these questions using the 'logical approach'. Try and practice it on some similar questions. Try to put your pen/pencil away and focus on each line of the question at a time. Try and work out what the line tells you. By the time you read the question stem, you might have the answer in your head or some manipulation might give it. Try to do all this without writing anything. It is going to be a pain in the beginning since you would not be use to solving without writing everything down. Also, some questions will involve some calculations which you might want to do on a piece of paper. But one sheet of paper should be enough for 20 questions. If it isn't, that means you missed out on the direct approach and are using way too much time.
For starters, when you come across a question in which you take a lot of time, put it up on this forum. You will get 1 min solutions to most such questions.