I am a student of class 12, science stream. I want to be an Indian Forest Officer. What are the important things, I should follow to be an Indian Forest Officer ?

Dear Anirban, you are having a good goal, which rarely crosses minds of other people.To be an Indian Forest Officer, you have to appear for IFS offline exam, which has total 6 number of attempts.

The Indian Forest Service (IFS) is conducted by UPSC) for the recruitment officers at the All India level by the Government of India for the scientific management of its forests.

• There are some fitness criterias:You must be physically fit according to the physical standards for admission to Indian Forest Service Examination. Candidates are advised to visit the IFS official notification to check the detailed rules and regulations.
• You must be a citizen of India.
• You should be holding a Bachelor’s degree with at least one of the subjects namely, Animal Husbandry & Veterinary Science, Botany, Chemistry, Geology, Mathematics, Physics, Statistics and Zoology or a Bachelor’s degree in Agriculture or Forestry or Engineering of a recognised university or equivalent. Appearing candidates can also apply.
• You should be within the age limit range of 21-32. (There are age relaxations depending on candidate's category).

Check the official PDF for more information

https://www.upsc.gov.in/sites/default/files/Notification-IFoSE_2020_N_Engl.pdf

I wish you good luck!