I learned English as a foreign language. Born and raised in China, I remember myself fearing mispronouncing words whenever I spoke, unwilling to use vocabulary that I'm not sure of how to pronounce for fear of being ridiculed or mocked at. During my long and arduous journey of perfecting my English abilities and learning other languages, I've come to realize that your accuracy of pronunciation really doesn't matter as much as you may think in daily conversation. Of course there is merit in trying to improve, but the fact is that the people I was talking with (especially native speakers) couldn't care less about whether or not I was speaking with a perfect accent. It's completely natural for all beginners to not "master" pronunciation, and the fear of "doing it wrong" is often the biggest deterrent that I, and a lot of my students now, will ever face.
Another thing I've noticed during my years teaching for the TOEFL is that when students practice for the speaking section, they often begin to get super nervous after making one small grammatical mistake, causing them to mess up the rest of their sentence and become super flustered. There is merit in trying to correct your grammatical mistakes, but students often overdo this and become very embarrassed by one small error, compromising their comprehensibility when conversing with someone else. When you make a mistake while speaking (which is almost unavoidable), remember that you should never compromise the ability for someone else to understand you, and if the mistake is small, simply carry on with your sentence. People will notice/care less than you expect.