Is there a proper way to measure them? I simply use a 2 cup measuring cup

That is what I do also, but I really question certain veggies such as kale. The food tag on kale says 1 cup is 67g, but when I put it into a measuring cup then weigh it, it's only about 20g. It can be confusing. My coach said to use 2 measuring cups.

I also use the simple measuring cup and find it works for me, I am always full at the end of my lunch

I use the water displacement method. I put 2 cups of water in a 4 cup measuring cup. Then I add my veggies until the water level moves up to 4 cups. Voila...2 cups of veggies!

I don't measure anymore. I started eyeballing it about week 5 or so. Am I the only one? I eat the same veggies over and over so I know what 2 cups looks like at this point.

I am with you, after you eat the same veggies all the time you kinda know how much it is. IF I eat something different I'll measure it a few times but that is it

Ha - isn't it the truth! And I got tired of washing out the measuring cup

I don't usually measure my veggies either. I did in the beginning but now I pretty much know what 2 cups looks like.