You can follow the curve of the infield.
Go straight down and back in foul territory, following the line, parallel, and then follow the curve of the infield, starting at the infield and go out.
Once in a while, I'll follow the fence and go in, but then the curve of the fence isn't always the same as the curve of the infield, so once you get closer to the stands, you end up with patchwork mowing right on the edge of the infield.
I try to keep the patchwork stuff in the corners out by the corners of the outfield.
Another thing is to start a home plate, and line up with the pitchers mound.
Then pick a spot as far out on the horizon as you can, and head straight for that. This will give you a starting point for having lines that are going to go straight out from the center of the stands.
You can mow one side of the field, then have to come back and mow the other side.
This one is a little tricky, since the team isn't going to want you to drive straight over the pitchers mound with the mower either, so you'll have to set up, drive to the mound, go around the mound, and then set up again.
If you've got someone with you, or something to stand on home plate, you could also start out in centerfield and come in, but you can't see home plate from there, so you'll need something higher than ground level.
The problem with the designs that you see on MLB, is that they've got more specialized equipment than we do, in order to make any profit at what we're doing.
I'm not about to go out an roll a star in the middle of the field like what was at the All-Star game a couple of years ago.
Plus, most likely, you're not going to have the quality of turf to work with either.
Give thanks, for all that He has given.