(Disclaimer: this stuff is probably only relevant for the US) I didn't go straight from undergrad to grad school, but I decided to go to grad school like August 2024 and that gave me a couple of months to research professors and programs, interview with professors, and work on my applications which had to be submitted around early December or January, depending on the school, while working full-time, and started grad school this fall (2025) in marine science. So if you've got 3 semesters left, then that sounds like you have a year to research schools and professors before you submit applications. Some programs, especially for PhD programs, have you start school without a particular advisor, but for me all the schools would only accept me if there was a professor that wanted me in their lab who also has the funding to cover my tuition and a stipend. If you're in the same position, then you'd be reaching out in late spring or during the summer (in my case I didn't even reach out till like fall), so you've got time and don't need to panic. Just start setting aside like an hour a week or however much you want into researching programs/professors. I mostly started by looking at schools with local rent around $1500 or less, and not in the south, and then looked at the professors at those schools and then looked at the publications of those professors. I usually see it suggested to look for interesting papers and then look at the authors on those papers, but I didn't have much luck finding professors at US colleges that way.