On top of the resources below, local universities also offer language courses that are worth checking out. Many cities also offer language exchange events (sometimes several in a week, held in universities, cafes, restaurants, etc.). These events help you meet new people while getting out of your comfort zone to speak in the language you want to practice.
When you’re ready to take an exam to prove your proficiency, always make sure you choose an exam that is accepted in the institute you want to apply to, and that you book a few weeks in advance and keep the deadlines in mind when doing so.