To expand a bit on what Gedstar said, we don't know you from the proverbial hole-in-the-ground. We don't know if you are 8 or 80 years old, we don't know if you are a doper or straight as an arrow, we don't your other likes and dislikes, the importance of humor or nostalgia to you, and certainly don't know any of these things about your friend. In addition, we don't know if you are going to have this printed and framed (...if so, how large...) or viewed on a computer, we don't know your level of skill with Photoshop, etc. etc. etc.
So give us all the above info + maybe some examples of collages you like, and we will be happy to try to help you out. Without it, we are shooting completely in the dark, and most likely like 99% of what we would suggest, your or your friend would instantly hate because we don't know even the most basic things about you.
HTH,
Tom M