How to recover from thin content penalty?

Hello, my site received this thin content penalty. I was ranking 1st for 1 year or more for some competitive terms. Some of my friends received that too. Now my site is at the 5-6 pages of google.

What would be the best approach to rank again and what to do before sending reconsideration request?

How long in your experience reconsideration lasts?

Steps i done: Added more quality content to my page also some images. I have just a few pages on my website but made sure all pages get…

How to recover from thin content penalty?