Everyone of my clients hates this suggestion. But it works. Speak slowly to improve your accent.
As with any new skill, your new accent will take practice. When we learn a new skill we take our time and practice it slowly at first. Think of when you learned to write. It was a slow process at first. As time went on, you got faster and faster. Now, you don’t even think about it much.
Give yourself the time to learn a new accent by speaking slowly.