What shoud be done to retrieve lost data?

[Sweetoo]

I accidentally format my htc phone and i lost everything. All my photos etc etc. I did not do any backup either. Is there a way so that i can retrieve back my photos plz?

 

[Mooncatt]

Did you at least have Google Photos running and set to backup photos automatically? If not, then you're most likely going to be out of luck. If you had your phone encrypted, then even forensics level recovery software may not be able to get anything back.