Graduate Studies is nothing like your undergraduate, it is one hundred times better. However, you must make sure that you choose a topic that you are interested in for your MRP (Major Research Paper) or Thesis. If you do, it will be a great experience. The biggest lessons you will learn will not be in the classrooms, but from your seminar sessions with your own students, one on ones with your professors and advisors but mostly from the people in your cohort. It is a lot of work, but it worth every minute.
Make sure you need grad school for your future career before you do it. Reach out to other grad students while you're in undergrad; most people will be more than happy to share their experiences.
Get involved in the community. Grad school is more than your research project; expand your contributions beyond your field of research and into the community where you are working.
I heard this quote when I first started my Master's: "Your project at the end is not going to be the same as when you started". Although your overall deliverables/outcomes might stay the same, how it gets done is very likely to shift. Those who are adaptive to change, take proactive measures to complete tasks timely, and are willing to go outside of their comfort zone will be the most resilient.
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.
My best advice for prospective grad students would be to not be afraid to put yourself out there to the individuals you want to work with or those you believe to be the best sources of information. You are your best advocate! I would suggest doing as much research as possible on different graduate programs at various institutions, as well as the research being conducted to find the best fit for yourself. In my experience, asking current grad students how their experience was and how they achieved their goals was extremely helpful as they provided their authentic opinion.
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.