When touring graduate schools, it's crucial to assess the approachability of potential supervisors and the communication dynamics between faculty and students. Observing the camaraderie among current graduate students can provide insights into the program's environment. Inquire about research assistant funding for the first summer, especially if your focus is on a specific field like cosmology, to avoid unexpected financial burdens. Additionally, request preparation materials for the PhD qualifier, as many schools allow a no-penalty attempt during the first summer, which can significantly ease the transition into graduate studies.