A list of advice from my experience in grad school:
1. It takes a lot of courage and time to accept a simple statement that a PhD research project is not simply a continuation of your undergraduate program. Until it does not convince you, PhD is a daunting task. Educate yourself: nobody did a particular task, that’s why it’s a research problem.
2. After a certain time, persistence is the only key to achieving end goals. One of the dazzling things about PhD journey is that it allows us to stumble along, getting it wrong time after the time, and feel perfectly fine as long as we learn something new.
3. Discuss expectations and obstacles with your supervisor. Do networking and collaborations with others in your field.
4. Write everything you do — even if it doesn’t work. You need to write that down because you cannot remember tiny details for long.
5. Don’t go after perfection, chase progress. A finished thesis is the best thesis.
At the end, PhD is full of marvelous experiences and gives you the freedom to work on something that fascinates you. Cheers!