Travel / I'm half-Polish and I'm Planning a Trip to Poland - tickets, historical landmarks? [36]

Hello I am planning a trip to Poland once I graduate high school this year, a month before I start college. I am half polish and I really want to experience Poland first hand. I just wanted some tips on where I should visit. My close friend told me I should stay in Krakow, because it is a great place to party. I want to experience that but I also want to see some historical landmarks. Does anyone have a suggestion for a great airline with reasonable priced tickets? also what should I bring with me? Anything specific? I need to start planning soon and I'm very excited and anxious!! I was also told that in most major cities in Poland that I could easily find someone who speaks english..is this true? I was planning on learning Polish better to prepare for my trip. Thanks for the help!