Hi, and welcome! I think you have started a project. None of these shots are going to be anything great, but now that you've begun the process:
Get a different venue. The grass is not going to be the best ground. Try different places, including hard floors, carpeting, etc. with some kind of uniform backdrop, such as a painted wall.
Try to catch the puppy in a more relaxed, even pensive moment (not going to be easy).
Try to get a shot of the eyes looking at the camera, if possible.
Use fill flash or bounced flash (if no speedlight then your built-in flash can be made to work by using a modifier).
If you can't get close without exciting the puppy, then crop much closer in post.
Plan on trying this many times until you get a few good shots.