How do you get your family members to join?

I would have to say yes. If you sit down every week on the same day and plan for the week what you would like to cook or prepare for each meal then you will have a shopping list. Once you have picked up the items that you need it is then easy to prepare each meal as you plan.
If you want to be even more efficient you can actually prep a lot of the food before hand when you bring it home from shopping this is to help the daunting task of cooking a meal to become much easier and smoother