I'm going to make this simple.
My fist represents an approximate CUP measure - a little more, really.
What I can hold in my hand represents an approximate HALF CUP measure.
For this week.....
take a look at your food.
If it's a green vegetable (not a bean)... eat all you want BUT eyeball it so you get a feel for what you are eating
If it's a fresh juicy fruit or a protein source (like chicken or yogurt) ... measure by the fist..... that's an approximate serving
If it's a starchy vegetable (beans, potato or corn), a starchy fruit (banana), a grain (brown rice, oatmeal), a casserole or cream soup.... use the handful concept.
If it's a SLICE (whole grain bread or cheese) .... that's a serving.
While you are eyeballing... strive for balance...
Meals: 1-2 svgs grain/bread/starch; 1 protein; 2-3 veggie/fruits
Snacks: veggie/fruit; protein
Remember: I am not a doctor.... nor am I a nutritionist... I'm just a person like you trying to make health simple.