In my opinion, there are 2 things you can do.
1) talk to the mirror
2) talk to a language partner or an affordable tutor
By talking to yourself, you can practice your toungue. Speaking the new language out loud is incredibly helpful. You need to start off really slow. After 20-30 reps saying the same thing, you will see the difference. This was how I practiced speaking English every day.
It is inevitable to find a real partner/tutor to pinpoint the mistakes you have. This way you can learn in a faster pace. I have tried both. For language partner, it might take 2 hours every time and it might not be productive sometimes. Some people speak the language naturally but don't know why and are not very keen to correct you. I now prefer having a teacher. Learning a language doesn't happen overnight. My advice is to find affordable teachers and let them practice with you every day for 1 hour. It will be very productive.
I have tried a language marathon/sprint from another platform to learn English for 90 days non-stop. It wasn't very good in my opinion because they were group lessons. I now created my own approach. I have 5 English teachers who charge me only $10US/hour (you can adjust whatever affordable for you). My English improvement has been furious because now I can write this long comment and you can understand me so far.
Good luck on your journey.