JoLee for ease in remembering how to order something in your coffee you only need to use the single word leche for milk and crema for cream. While fresca does means fresh, many people in Mexico use it more in terms of fresh air, cool air, that sort of thing.
However be aware even if you do ask for crema, it's very possible you'll still get milk. Not because they're trying to con you, rather because many people in Mexico (just like in the US or Canada) just use the word cream for any dairy product to be put in their coffee.
If you desire genuine cream for your coffee try por favor Crema Real or Verdadera Crema. Using either choice is specific to requesting real cream only
Here is a link I'll think you'll find very useful. Just type in the English word you want translated, and the not only will the Spanish version come up but over to the right you'll see a button marked audio. Hit the button with your speakers on and you'll hear the correct pronunciation too.