Spoken production
Spoken production no. 1
At university, I had a course called Phonetics and phonology. I didn't know what to expect. It ended up helping me with pronunciation so much! All the symbols of the phonetic alphabet are useful and suddenly, the weird letters in dictionaires make sense. That is why I find learning the phonetic alphabet important. In online dictionaires, you can usually also listen to the word and hear the stress. Because of learning phonemic sounds, I've realized that some words, which were hard to pronounce for me before, are actually easy.
Here's a basic introduction to the alphabet: https://www.youtube.com/watch?v=vzsQkjX4fD8
And I recommend Cambridge dictionary: https://dictionary.cambridge.org/
Spoken production no. 2
What helped me the most in improving my speaking skills was going to an English-speaking country or just any country where English is spoken. There, I was forced to communicate and somehow explain myself. But I know this might be time and money consuming, so here's another learning tip:
Warm up your voice. I know from my own experience that if I don't speak for a long time and suddenly want to, it's hard. To make articulation easier, I use this short video: https://www.youtube.com/watch?v=EB8sY2PNweY
I also learnt that accents are actually important. Although I used correct grammar, I often switched accents depending on the words. It doesn't sound natural, so I chose to stick with RP (British pronunciation). Here's an interesting article that can help you in deciding which accent to choose: https://pronunciationwithemma.com/how-to-master-british-vs-american-english-pronunciation-key-differences-explained/