My first piece advice to prospective grad students would be to find a lab or an advisor that you mesh well with and are excited about working with. If you are on the same page and feel comfortable from the start, it makes all the difference. After that, trust yourself and your abilities! You are capable of more than you think.
Absolutely take the time to reach out to current students, alumni, and faculty members affiliated with the grad programs of consideration. Your grad school experience will very much be influenced by the people you are surrounded by during your education and the culture of the program. Hearing from other's experiences and talking to current students is one of the best ways to find the right fit for you.
Find what interests you. Many other grad students are much younger than I am and will be entering a life's career following completion of their studies. Looking back, I think it's important to pursue your passion and let the career, money, etc., come from that. During studies, stay on top of things. At the same time, don't neglect other outlets, pursuits, interests: things have a way of connecting in unexpected ways.
In graduate studies, you will work harder than you have ever worked, but it is going to be so rewarding. There are experts in every field at the University of Guelph, who will support you and offer so many resources that are available to help you succeed. You are also going to meet some incredible people along the way, especially since there is such strong comradery among fellow graduate students. I know this is a cliché, but I think you get out of your time here what you put into it, and there are so many opportunities available to take advantage of, to ensure you have a great experience.
I would encourage all prospective graduate students to research their program of interest and speak directly to faculty prior to applying as this can ensure that your research goals align with your prospective advisor/program of choice.
Coming from New York City, Guelph was definitely different but I would say it was a relief. It truly grounded me to not be amongst the hustle and bustle every day and it's a small town full of nice people.