This is the most common query I receive in the comments and in the email from IAS aspirants; How do I start preparing for the IAS exam? To prepare for IAS 2013 exam you will require three things: a proper plan or approach, the right study materials, and commitment.
Planning is imperative when you decide to appear for the Prelims. Deciding to take the exam 4 or 5 months before the Prelims is not a very smart strategy as you have to cover a wide syllabus and go through numerous books and magazines, even though it is possible to prepare for Prelims in 4 months. But I always advise you should start preparing at least 10 months prior to the next year's Prelims and 12 months ideally, if possible. So if you are targeting IAS 2013 to be held in May 2013 then ideally start preparing from June 2012 itself.
The first step is to know the paper 1 and paper 2 syllabus in detail. Many IAS aspirants get confused about Prelims preparation and subject selection for Mains at this stage which is quite wrong. You DON'T have to select optional subjects in Prelims, that task is for Mains exam. And quite frankly if you are just starting out don't worry too much about selecting optionals for the Mains at this stage. Rather you should concentrate on the Prelims preparation. Optional selection comes later after you've gained some knowledge of the Prelims topics and have developed a basic understanding about the Civil Services exam. If and when you do decide to prepare for Mains, you can get my individual guidance for selecting optional subjects for Mains.
Next, decide which topics from paper 1 and or paper 2 you will cover first. Let's say you start with Indian History from paper 1 which you study in the morning and afternoon and in the evening you take up mental ability from Paper 2. I always suggest you should no prepare more than 2 topics simultaneously. Rather, you should first cover one or two topics completely before moving to the next. I suggest you go through this Prelims Preparation guide to understand the IAS Preparation steps and strategy in detail. Notification for IAS 2013