Identify your passion and reason(s) for wanting to become a graduate student. Write them down, type it up, post it large and visibly on your desk or wherever you do your work so that it remains a constant reminder of why you are doing what you are doing and will motivate you through the hard times that every graduate student has and does go through, so that you can always see the light at the end of the tunnel.
I would advise a prospective graduate student to do their homework before contacting prospective advisors. Check out their profile on the University website, read their most recent paper, and even reach out to a senior graduate student currently in the lab!
My research dealt with using biostimulants as environmentally friendly alternatives to fungicides, for preventing dollar spot disease, which is one of the most prevalent disease that affects turfgrass on golf courses worldwide. My research will hopefully help to identify species and cultivars of turfgrass that respond positively to various biostimulant applications and therefore have a lower disease incidence. This will potentially allow golf course managers to use fewer fungicides in the future by switching to biostimulant applications, which will reduce the environmental impact that they have on the surrounding ecosystems.
I would tell any prospective grad students to visit the campuses they are applying to, and talk to students in their program(s) of interest! A major factor in my staying at Guelph was the campus community, and knowing that I would be supported throughout my studies in not only my academics, but also through the social atmosphere on campus.
Pursue research that you are passionate about and that inspires you. Graduate studies are a lot of work and can be difficult, and if you're not passionate about your research then you probably won't enjoy it. That being said, don't be afraid to step out of your comfort zone and experience new things, whether that be academically or personally. Also, don't be afraid to get involved, some of my greatest experiences at the University of Guelph have been outside of the classroom.
Do your research: on the lab, on the faculty, on the department and on the city itself. There are so many different programs/departments and it's imperative you know what you're getting into. Speak to students that are currently in the lab or have recently graduated to get an idea of how things work. There are going to be some tough times in your program and you want to make sure you're surrounded by people that want to support you and help you get through, to be successful.
While it's true that you should work hard to reach your goal, burnout is real. Allow yourself to take breaks when needed; take a nap, play video games, and laugh at some memes. Life will feel less annoying.
Be prepared. Look around first and then come here. Do your homework when you're looking at programs and remember that you stand a real chance of working with OMAFRA and OMAFRA connected researchers here. They really are the best.