I think every student need to do erasmus once. They start a new life in another country and try to get used to different cultures of that country. Its not that hard to handle with it, believe me! Everybody will be so kind to you and try to help you when you looking for possibilities to live there and meet new people. And you wont be alone, there will be another students who has the same situation as yourself. you will travel, go to party, go to school and explore with them. You will discover yourself and it feels like you are living an another parallel life such an amazing. now I will tell you what do you need to do for start that experience with telling my story.
you need to past some exams at school as you know, of course with good english at least B1 level will be enough for you. then need to apply visa for the country you will start to live. but if you are from EU and you will start to live somewhere in EU you dont need it but I'm from Turkey so I needed to do that. then look somewhere to stay BUT NEVER FİND ANY FLAT FROM INTERNET! dont trust internet and wait to go that country and ask local people first. Some of friends of mine had a big trouble with trust somebody to rent a flat from internet. ESN club which is from university going to help you for accomodation so ask the school first!
then be social and dont be shy. You will meet people with ESN's help and start to go parties and another activities with them then you gonna have good friends which is has the same frequency as you and start to travel with them. I will share my travel diary with you :)