Let´s repeat a little bit to be sure that you can make an order in the cafe. So here are some phrases you could use to come up to the waiter/waitress.

Klient: Vabandage, kas ma saaksin tellida?

Ettekandja/kelner: Jaa, palun!

Klient: Ma sooviksin tellida.

Ettekandja/kelner: Jaa, ja mida teile?

Ettekandja/kelner: Palun, mida teile?

Klient: Palun mulle...