iPhone is no different from other jpg-only cameras Here is what I do, mostly in this order
1) delete the junk
2) light cropping, as this might effect the next step
3) exposure correct, possible "recovry" (use histogram to help judge)
4) white balance, using eyedroper tool
5) Now find the "best" images.
6) any kind of "editing" to change the best ones image, if required. Retouch, dodge, burn or whatever
7) Deleted more images (deleting improves the average quality of the library and save work in the next step.)
8) meta data and tags get added
You can not sharpen a photo until you have resized it for export. It is always bad to sharpen before re-sizing, it just adds noise.