Tips for increasing appraisal value?

[Dmitriy Yeshin]

Hi all. I am curious if some experienced people here can share some tips for increasing appraisal value? Given that square footage and location are fixed what can an investor improve that will raise the appraisal the most? For example would adding an extra bathroom vs updating kitchen provide highest ROI? Is there a difference between appraising a rented property (brrrr strategy) vs when selling a flip for example? Thank you all in advance.