Why was the rating for this so low? There is only one mistake, and it's not a real mistake!
In a café, I order a cup of apple juice and add some ices in it.
"will order" is ok, but usually people talk in present tense. Like, "I go to school," "I dance at parties." Same thing, "I order at a café."
I also like to have some pastry.
Besides is a tricky word. The meaning is close to "also," but it is a little different. See examples:
"I cannot go outside. Besides, I should study at home."
"We cannot be lovers. Besides, I am moving."
"I cannot go outside. It is ok because I should study at home."
"We cannot be lovers. It is ok because I am moving."
The meaning is closer to "it is ok because" than "also."
Sandwich is a favorite of mine as well.
Keep practicing! =)