Being such a multilingual and international university, studying at the University of Luxembourg implies the fact that you will probably have courses held in (at least) 2 languages (French/English, French/German etc). Even though you are already profficient in one or 2 languages, I think it is always room for improvement.
The UNI provides you with language courses for each semester for more than a reasonable price, you can find out more details here. Besides this, I would like to share with you some interesting websites where you can practise English, French of German for free:
Personally, I recommend www.memrise.com and www.duolinguo.com. These websites have a more creative approach towards teaching languages, are very user-friendly and quite fun. You can simply connect with your Facebook account and start learning.
Learning online, by yourself is not enough, especially if you want to improve your speaking. For this you have to get into real interactions with other persons. Tandem is a good idea and you can easily find a Tandem partner at the University or in general in Luxembourg, as people here are eager to learn languages.
Also, you can try the Polyglotte Club; its meetings take place every Tuesday at Le Foyer (Rue Heine). Here, you have the opportunity not only to speak German, French, English, Italian, and Luxembourgish with native speakers, but also to meet new people that just arrived in Luxembourg and why not, to make friends. The participation fee is just 1 euro/year for students.
How do you improve your languages? If you have more tips, please share them with us…