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.
I've been very privileged and lucky since coming to Guelph for my undergraduate degree back in 2010 as all of the opportunities I have been given have been gained through building strong relationships with faculty and staff on campus and finding mentors that have helped guide me along my career path. I've always found that the people on campus are incredibly giving and willing to devote their time to help out students. I've also found that simply starting with expressing an interest to be more involved and showing initiative can go a very long way to opening doors to new opportunities.
Always ask for help. When in doubt, ask; When not in doubt, ask. Enrolment in graduate courses can be very small, and grad life can sometimes feel isolating; so, try to form great bonds with other grad students. You have a lot in common! Try to take some time off to have fun, and when you inevitably encounter students pulling a tractor in September, do the opposite of what I did; and be cool! If you can, participate in the 3-minute thesis competition (3MT); it's a lot of fun!
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.
Grad school is demanding, but it's also an incredible opportunity for intellectual growth and discovery. Be prepared to work hard, face setbacks, and constantly learn. Find your passion. A strong foundation in your area of interest will fuel your motivation throughout the programme. Seek guidance, embrace the journey, and remember that your path is unique.
My advice to any prospective grad student is to not rush into graduate school without some self-reflection about your passions, what you love doing and what you would like to study. This is because grad school can be a challenging place but also incredibly rewarding as it teaches you how to read critically, learn systemically, and think deeply. As such, I invite potential students to engage in some introspection and self-reflection about your motivations, desires, and commitments as this is a weird (but wonderful) experience distinctive from both undergrad and from other jobs so its important to not rush into anything without thinking.