However much you do, you will have twice as much as you need.
I always do the same-ish food.
Either very small sandwiches or garlic bread Biscuits in the shape of the number they are turning Breadsticks artistically shoved in a jam jar Grapes or watermelon if it's hot Juice in those pop top bottles 'Vegemite crocodiles' which are sheet puff pastry slathered in Vegemite (or similar) sprinkled with cheese. Cut out with a crocodile cutter. I first did these only so I could hear people say 'pass the crocodiles'. And the cake
Having done several parties for DC I now know not to do too a lot of sandwiches or salad as it doesn't get eaten! We have to think about catering for Muslim (halal) and Jewish (kosher) friends so the following work well for most:-
Cucumber sticks Carrot sticks with little pits of hummus for dipping Cherry tomatoes Sliced peppers Mini sub rolls with jam or cheese Pizza slices Strawberries/grapes Mini breadsticks
I also do sausage rolls and mini sausages as DS insisted on them but make sure to store them in sealed tubs separate from other food and serve on separate plates