You need to do a lot of testing. I test so much that most of my peas don't make it into the house. When a pod looks fat, before it starts to yellow, pick it, pop open the pod and then eat the peas. If they seem sweet and ripe, all the peas that look the same should be ready for harvest. But you might want to test a few more first :-)

Don't hull them until you are ready to cook. They keep fresher longer in the fridge when they are whole. Just pop them into a plastic bag and put them in the crisper.

Fresh and uncooked is my favourite way to eat peas. But if you want to cook them, a bit of mint and butter goes well with lightly cooked peas. Lightly cooked peas are also nice in salads with tomatoes.

For something different, try Fresh Pea Soup:
Saute an onion in a pot in bit of oil until it is golden. Add a chopped potato, a bit of salt and 4 cups of water and cook on medium until the potato is soft. Then add 3 cups of fresh peas and cook until they are bright green. Puree in a blender of food processor. Serve it warm with a garnish of sour cream and chives, dill, mint or parsley.