How do I change new docs from opening in the upper left of my Desktop?

Some things like App's and Finder windows can be trained over time to reopen in a certain place. However I find that even that is hit and miss after shutting down and starting back up.

The best way to maintain all window locations is to only sleep and wake the system.

What applications are you using? What kind of documents are you talking about?

Although the Preview preferences list has settings in it for open and save dialog sizes, it does not appear to have a setting for initial display location. Thus, one gets to drag the window to a new location if upper-left is a long reach. Or one can electronically disappear the window in its default location, and snap it out to center screen, as I have done in the following AppleScript. This was tested on El Capitan 10.11.3, and I am using a 24 inch display. Assumption: Preview window and image are open, whether on top or under other windows.

-- move default Preview window to mid-screen.

if application "Preview" is running then

tell application "Finder" to set visible of process "Preview" to false

tell application "Preview"

tell front window

-- preserve image size from {x, y, w, h} in bounds

set {w, h} to {item 3, item 4} of (bounds of it as list)

end tell

end tell

tell application "Finder" to set the position of application process "Preview"'s front window to {700, 250, w, h}

activateapplication "Preview"

end if