Earlier responses to the speaking section on the TOEFL were graded by two human graders. Since August 2019, ETS has been using a single human rater along with their proprietary Speech Rater software. ETS appears to be using human raters to evaluate content, meaning and language while their Speech Rater software can evaluate your delivery for tone and hesitation as well as grammar.
You need to resist the temptation to translate your thoughts into English from your native language. When practising at home, spend time orally summarizing texts that you read into a few lines.
Pay attention to your pronunciation and to the speed at which you speak. The independent section of the speaking task requires that you speak on a familiar topic – describe it, state your personal preference, support it with examples and add your reasoning. For example: My favorite place to spend time when on vacation is the nearby park because I enjoy the peace and quiet and find it very relaxing.
For the integrated speaking task, you may have to refer to information presented in the question when recording your answer. Make sure you use appropriate vocabulary and signal words like "for example, in addition or I think that…" Vary the words you use as much as possible to keep the attention of the human grader.
Pace yourself while you speak so that you do not run out of time for the task or finish too early. Your score will depend on the content of your answer as well as your pace and pronunciation.
Here's how Improved English can help you achieve a great score on the TOEFL Speaking section.