This is a question with many answers, as there is no one way to write an acknowledgement in a thesis. However, there are some general guidelines that may be helpful to keep in mind.
First, it is important to keep the tone of your acknowledgement positive and upbeat. You want to express your gratitude to those who have helped you, without coming across as overly sentimental.
Second, it is helpful to be specific about what each person or institution you are thanking contributed to your work. For example, you might thank your advisor for their guidance, a colleague for their help with data collection, or a funding agency for their financial support.
Third, it is important to keep the acknowledgement relatively brief. This is not the place to list every single person who has ever helped you, nor is it the place to provide an extended explanation of what they did. A few well-chosen words will suffice.
With these guidelines in mind, below is a sample acknowledgement that you might use as a starting point for your own:
I would like to express my sincere gratitude to [Name 1], [Name 2], and [Name 3] for their help with this work. [Name 1] provided invaluable guidance and support throughout the project, while [Name 2] helped with data collection and [Name 3] assisted with the literature review. I would also like to thank [Institution 1], [Institution 2], and [Institution 3] for their financial support. Finally, I would like to extend a special thank you to my family and friends for their love and encouragement.