Okay, for starters, the language played a major role in the experience. I would highly recommend that one becomes familiar with the language of the place where the Erasmus+ trip is taking place. Use a good language app and try to watch some videos, series or movies in the respective language. It will make everything easier and more enjoyable.
Pack enough to be able to be comfortable but not too much because you will inevitably buy things there.
Get a general idea of what the place is like by researching it. This will give you an outline of what you want to see and where you want to go and it will save time trying to decide later.
If you are going to a sunny place: Bring. or. Buy. Sunscreen. And, use it! It will save you a lot of pain.
If you are making a budget try to be realistic. We all want to be a certain way but it's better to be real with yourself and then budget accordingly.
Finally, have fun responsibly. Be aware of your surroundings enough to be safe but not so much that you end up not having fun. Try new things, new food, talk to people, ask questions, take photos, look around... it goes by so fast that to not do so would be a travesty.
It is a wonderful opportunity and you get out of it what you put in ♡