Hey,

First of all, you ace the exam you can use the Telugu language as you might be well proficient in it. You have the liability to choose the Telugu language option in UPSC Exam. However, you need to note that You would not be able to write the IAS prelims exam in Telugu. Prelims is a multiple-choice exam in which you can only answer in English or Hindi. You can write the Mains (Descriptive exam) and Interview in any of the 21 languages recognised in our constitution, for example, you can write the Mains (Descriptive exam) and Interview in Telugu.

However, you choose any of the languages, the basic set of preparation remains the same:

• Make a suitable time table because the syllabus is extensive, you must ensure that you devote sufficient time to all areas and themes, and that no vital topic is overlooked in your UPSC preparation.
• Choose only standard reference books in the language chosen by you for UPSC Exam.
• Knowing the entire syllabus will assist you in determining which books you will need to study. It will also assist you in not missing any vital information.
• Solve as many mock papers and go through previous years questions paper.
• The UPSC preparation includes reading newspapers and keeping up with current events. Newspapers supply the candidate with a wealth of information about current events in the country and abroad.

Check the details over here : https://competition.careers360.com/articles/how-prepare-for-upsc-ias