Good space you have there. As all are recommending ..here are my few Rs 100 advice:
1. Get the sound absorbers -
https://www.amazon.in/Kadence-Cotto...SIEGUa9NBP8e9oFAEBMNUSi_CIVVtp2caAkDKEALw_wcB
2. Have a carpet esp right in front.
3. Ensure that speakers tweeter is at your ear position. Adjust their height.
4. Perform auto calibration in ur AVR every time u move any furniture.
5. Ensure all reflecting surfaces life windows / walls etc are covered with thick curtains or sound absorbing materials as per link above.
6. sub should be placed at the correct location.
7. The avr / projector should be placed at well ventilated zones as they get hot soon.
8. If you have atmos.. makes sure speakers are aligned in correct angles.
9. Your listening and watching position should be well calculated.
10. Proper room sealing to be done so as to avoid sound and pressure escaping the room. No .. i mean do not convert it to a vacuum chamber.
11. get rid of all glass / room decoration items.
12. Have speakers placed at correct distances from walls. Refer to their manuals.