The UPSC Prelims exam has two papers, GS Paper -I and GS Paper - II (CSAT). 

Reasoning forms the part of CSAT paper which is only qualifying in nature and the score is not counted for the cutoff. However, it is essential to secure a minimum of 33% marks in the exams. This makes it essential to prepare for the CSAT paper including reasoning as an important section.

Four types of reasoning questions are asked in the CSAT paper -

• Data interpretation (line graphs, data/numerical tables, bar graphs, pie charts, and combination charts)
• Data sufficiency
• Analytical reasoning
• Logical reasoning - includes questions on  Coding-Decoding, Seating Arrangement, Syllogism, Blood Relations, Series Completion, Logical Connectives, and Venn diagrams.

Practice, Accuracy, and Speed are the three fundamentals that a candidate needs to work on to excel in the reasoning section of CSAT paper.

However, before we delve into the strategy and tips to prepare it is important to understand why does CSAT paper includes a specific section on reasoning. This is one of those questions that often arises in the minds of UPSC aspirants.

Reasoning is an important skill for any administrator. To be good and effective, it is significant that an administrator considers not only the subjective situations but the facts and numbers in front of him/her and takes logical, practical and viable decisions on that basis. UPSC assesses the candidates on this basis through the reasoning section. The reasoning section focuses on understanding, organizing, sorting, problem-solving, interpreting and decision-making. 

Crucial factors  forming the base of DI and reasoning questions:

• Problem Structure
• Approach/Method/Simplification
• Tips/tricks
• Time management
• Accuracy

Preparation Strategy and Tips

• Familiarize yourself with the syllabus. 
• Get clarity about the pattern of questions asked in the exam.
• Devote the needed and sufficient time for preparation.
• Learn about your strengths and weaknesses and study accordingly.
• Work on the basics.  Often the solution of reasoning questions lies in its simplification.
• Learn the best tips and tricks and keep a track of the latest trends as time management is directly related to this.
• Do not just rely on the books but explore other modes of learning like Youtube videos, digital media platforms, newspapers, competitive exam magazines, etc. You can find easy-to-use tricks and tips in these which may be missing in the reference material.
• While solving questions, remember not to use too many tricks together. But apply one method or trick at a time.
• Take mock tests. For the reasoning section, practice is really crucial.
• Solve previous year question papers to learn about the pattern of questions asked in the exam. 
• Revision is the key, no matter what the subject is.
• Lastly, do not ignore or delay your preparation for the reasoning section thinking that it only forms a part of the qualifying paper.