How do I mark items as "must have"?

Every registry item has a priority: Must Have, Nice to Have, or Low. You can set it when you add an item. To change it later, open the item and update the Priority field.

The registry's default sort is Must Have first, so your top picks show up at the top. Use the Sort menu on the All Items tab to change the order (Still needed, Newest, Oldest, A → Z, or Price).