Something relevant that may well be worth your time doing.
If you already know where you are going to be living then have a look at the nearby places and events.
This may seems like a strange answer on a work basis but what if you know where you can go to burn off steam after a long day of work it can really reduce your stress and increase your motivation and productivity.
If you know who you are going to be working with in a team perhaps you could ask if it would be appropriate to have a work contact email address or phone number. An important part of a workplace is knowing your team, now im not suggesting you phone them every day and have 6 hour conversations about lunch. But what you can do is ask relevant questions about the technologies you'll be using, you can ask if there is any documentation or help sheets you could ask for those to get familiar with what you will be working on long before you get to work. But most importantly it breaks down that initial wall between you all allowing you to fit more seamlessly into the team and the environment allowing you to focus more on your work than having to worry about conversing with the team
Please note: The above might not be acceptable behaviour, i don't know the type of environment you are going into so please use your judgement on this.
Something you might want to invest in is perhaps see if your favourite book (in your native language) has been written in english. This means you can have a copy of each and can practice reading it, you will already know roughly what the story is and this can go a long way in helping you to gain more experience in the general structure and useage of the language.
But most importantly, dont panic, and dont worry. Once you are in a country (whatever your age) most people do pick up the language very quickly, no-one will expect you to be fluent, just take your time when structuring your sentences and think over what you want to say before you say it and dont worry too much, youll pick it up im sure :)