The right eye is always listed first on your vision prescription; it's usually marked "OD" for oculus dexter, and the left eye is "OS" for oculus sinister. You can also check your right and left eye powers right in your Aveo account.
To make your mornings easier, mark your contact lens boxes so you can quickly tell the left and right lenses apart! And when inserting your contacts, start with the same eye every time. That way, you'll be less likely to get your lenses mixed up.