A lot of good advice here, I've little to add except to be consistent with your commands.
Gracie tests the Come command too. I'll say Come, you can see her little brain working, Ok Momma, here I come. She'll take a step, cock her head
and then turn and go in the other direction. Little stinker, but it's so cute that I can't get mad at her. I just help her to remember, I'm the Momma and what I say goes.
One thing that works with Gracie when she does this is for me to immediately turn
my back on her, I wave my hands in the air and make a funny noise. She'll come immediately to see what new game I'm playing. When she walks around in front of me I say Come to her again and she'll walk right to me. I praise her and then we move on. I am still working with her on leash to be consistent with the command, she's only 8 months old and I know she will eventually get it down pat. My DH saw me do this once in the backyard and he thought I'd lost my mind. But it works, so I'll keep doing it when I need to.
As for the grass thing, Gracie from day one has always eaten grass. Grass, wood, bugs, dirt, rocks...anything she could put into her mouth. And when you are only 3 inches off the ground,
everything looks appealing. It's all part of the puppy stage. She's tapering off some now, at least I haven't seen her eat any clumps of dirt lately
But she still enjoys a bite or two of grass. I don't believe it harms them in any way, so I'm not worried about it. I'd be thrilled if grass was the strangest thing she put into her mouth.