The first thing that is recommended when you looking for information about different university that interest you, is to download and read all the reports from others student that have been in the specific university you choose. One of the thing that appears regularly in these reports, is the difficulty that every student encountered when they are abroad. We all know the difficulty when you want to have a normal conversation in a different language, but there is some tips for you to quickly be able to understand and be understandable by other english, native or not, students.
I have the opporutinity to traval around many countries since I am young, whether it's with my family, my friends or by my own, and compared to other french student that I met since I'm Hertfordshire, I seems that I have some facilities to speak in english compared to other french student who generally struggle. But I'm practicing a lot for the last couples years now, and there's a lot of ways to practice.
The first one, is to familiarise with your environment, choose an accomodation where you can talk with other international student , which can also help you, or if you already have a good english, you can decide to live with native english speakers (from United Kingdom, United States, Australia, etc….). The problem is that french people here are always with their group of french friends and at the end they still struggle. Talking will help you to be more confident with your english and will able you to find alternatives when you can't find your words for a specific sentence. It will also improve your listening skills, so you'll never be lost in a conversation.
The second one, is to continue to practice by watching video on Youtube, Televsion shows and series, listen to radio in english. For all these four solution, the best one is to watch videos on Youtube, first because you can decide your content, every Youtube channel that you regularly check probably exist in english, find them will replace your french habits with english (and because you know the subject in your language and the vocabulary you'll easily find the translation), second because the new Youtube system can add captions/subtitles to the video you're watching, even if you cannot understand due to the accent of the speaker, you will read it, last, it's the most simply way to improve your skills by just watching your favorite videos (you'll enjoy it because that's the same video that you usually watch but in another language).
The last one, is by doing activities. Go outside, yes even in nightclubs it works because you'll have discussion with other people. Go to the closest cinema (if they have caption it will be helpful), ask some information when you travelling in your country for whatever activity it could be, or something simple, when you go to shop to buy some food, ask to an employee for what you're looking for, it could give you some useful vocabulary.
By just using these 3 solutions, you'll push your english a step further, and because it cost nothing, at the end of your abroad you'll be back with a more fluent english.