Get. A. Therapist. You will need one. A PhD is a marathon, not a sprint (at least in the US, PhD programs are about 5 years on average; in other countries, you’ll need to do a Master’s first, so your total time is about the same). You’ll have to deal with Reviewer 2, failing experiments, negative feedback, and constant comparison with peers who are all seemingly succeeding at everything (they’re not). But if you’re that against a therapist, there’s always drugs.
Automate when you can. This may not apply to some fields, but at least in my field, a lot of research involves sub-tasks that are repetitive. Automation can take multiple forms. For example, I wrote helper libraries to do data preprocessing that’s repetitive so that later that code is a library call away (and it also follows the DRY principle).
Make time for hobbies/leisure. It’s easy to get absorbed in your work. Make sure you have a life outside work, whether that’s cooking, working out, game nights, or whatever.
Set short- and long-term goals. Set goals for the short term (say the next 6 months) and the long term (post-graduation plans). Make plans to work towards those goals. What’s your next paper going to be on, and what do you need to get there? What job do you want post-graduation, and how can you be competitive as an applicant?
Stay up to date and organized. This one is important. New research comes out all the time. You will absolutely need a way to be able to find relevant papers, judge their quality, organize them in your library, and gather their main points. Might I recommend Zotero or maybe EndNote?
Take time off. It’s easy to be that student who works all the time. That student always burns out. Set boundaries, and take time off when you need it (and you will). Consider it an investment in your sanity.
Practice digital hygeine. Backup frequently (I recommend once a week). Backup multiple copies (I recommend the 3-2-1 rule). If you’re on Windows or macOS, get an antivirus. Organize your files well. Avoid malware.