Learn the "leave it" command.
Change of plans. Planned on doing multiple sessions of backyard training where there are few distractions, but I didn't break away from work to train in the backyard. Sadie needs exercise, so we went to field to play fetch after work. She did some long and short fetches.
For the long fetches, I threw the ball while Sadie was in a sit, walked away from her to make a triangle with the ball, Sadie and me at the three points. From a distance made hand signals for down, sit. She did well. Used verbal commands too. Again she did well. Practiced recal, which she did with no issues. When she reached me, I gave her the release of free to fetch the ball. She got it and brought it back right away. Still is slow to drop, however.
Used short fetches to work on drop. I held two balls, threw one a short distance and let Sadie get it and bring it back. When she returned, she was quick to drop the ball - seeing the other ball in my hand. Just before she dropped, I gave the command to drop. As soon as she dropped, I marked with "yes, good girl!" Then threw another short fetch. Repeated this until I saw she was tiring.
More "leave it", "drop it", and attentiveness training.