If you want to do Russian translation, you must be confident first, don't doubt your ability, and don't be afraid. If you want to do this job, you must work hard and there will be setbacks. Mainly depends on how you overcome them.
As for the specific methods, you can practice on various websites first (this will facilitate your vocabulary, because what you have learned in school is far from enough)-then choose a purposeful translation for the industry you are interested in (translation must be professional, you can't know everything, but you can't do everything)-find a translation forum, and let everyone list your achievements one by one for criticism and guidance-this will accumulate more experience.
To answer your second question:
Russian translation qualification certificate is useful and will be used by translation companies. Of course, this is also a test of your strength. But don't be too serious.
If you really want to be a translator in the future, then you should be prepared for hardship, because you should keep accumulating and learning. Translation is hard work, but it is interesting. I hope you can find your own position soon!