Don't. They killed a good product, Picasa, which didn't have these problems because it didn't need to solve them.
There's no way Google Photos - or any cloud solution - will be an adequate replacement to handle my 100GB+ library of JPEGs, RAW files, and videos, with instant editing and access to all of it -- if only because it doesn't take a second to pull 100GB of data from the net!
Not everything needs to be cloud-based -- but not according to Google's vision. Picasa still does a fine job for me, but I have to preserve my copy of the installer because Google wouldn't want me to have it any more.