Accent softening with highly qualified phonetics and speech teacher, 20+ years' experience.

I've been working with Lindsey for several years now to refine my English pronunciation, and I can't recommend her highly enough.
As a German native speaker, my goal was to move away from a noticeable international accent toward British Received Pronunciation, and she has been the perfect guide on my journey.
Her ear is remarkable. She picks up on the subtlest vowel shifts, intonation patterns, and consonant placements that I would never have noticed on my own. More importantly, she knows exactly how to explain what needs to change and gives me practical exercises to actually make it stick. After a couple of months, there was already a significant improvement.
Accent work can be a long-term project, depending on where you stand and what you want to achieve, but progress never felt slow, especially as Lindsey keeps things motivating and varied. We've worked on everything from individual sounds to rhythm, stress, and the natural flow / melody of connected speech. She also tailors the material to my interests, which makes the practice feel genuinely engaging rather than mechanical.
After several years of regular lessons (once a week), the difference in how I sound is enormous. Native speakers quite often comment on my accent, guessing I've spent significant time in the UK, also sometimes considering that I might be Australian (as there are still the occasional little hiccups that give me away as a non-native speaker of British English, but I think we are getting there). To non-British natives of English, I sound like a Brit.
If you're serious about improving your accent and willing to put in the work, you won't find a better teacher.