"What is the best way for me to keep birds from hitting my large picture windows?"
Bird-window strikes are a common occurrence especially during fall and spring migration. Unfortunately, the majority of strikes end in direct mortality of the bird or the killing of a stunned bird by scavengers such as outdoor cats. The good news is that there are ways to help birds avoid your windows.
During nighttime migration, birds that enter a lit area become disoriented, are reluctant to reenter the darkness, and commonly hit windows or other structures. Therefore, one of the easiest solutions is to simply turn off all indoor and outdoor lights at night. Window strikes during the day occur because birds see a reflection of outdoor vegetation or sky making the window appear to be a passable space.
To help birds see windows during the day there are a few different options. One is to paint patterns on windows or use window decals. If using decals, I would suggest placing the decal on the outside of the window as they seem to not show through windows all of the time. Another option is to place netting outside your windows. Lastly, if birds are forced to slow down before reaching a window, a strike may not be fatal. You can encourage birds to slow down by placing feeders and vegetation very close (within a few feet) of your window.
The American Bird Conservancy gives more detailed tips on avoiding bird-window strikes on their website.