"I am not the same, having seen the moon shine on the other side of the world." - Mary Anne Radmacher.
Cusco is not Peru: even though Cusco is the main tourist attraction, and a beautiful one, Peru has tons of amazing places to visit and discover. Take some time to get to know some of them, they will take your breath away.
Always carry some cash: specially when traveling inside Peru, some small businesses do not have credit card payment options so it is best to carry some cash with you.
Take i t slow in altitude: when traveling to high altitude places or hiking, take it slow the first day and acclimatize, it is important to get used to the altitude before going on hikes or exploring. Coca tea helps a lot!.
Eat!: all the different regions of Peru have different typical foods, my advice is to always try the different options every region has to offer.