At the door, state your party size: "A table for two, please." For ordering, two all-purpose patterns cover everything: "I'll have + dish" or "Could I get + dish, please?" — no complex grammar needed; that's how native speakers order too.
🔊 The all-purpose ordering phrase: Could I get ... please?
💡Can't pronounce the dish? Point at the menu and say "I'll have this one, please." With your finger on the item, it's completely natural — servers see it every day.