I like working a pair of Lodestones (naturally magnetic rocks) whenever two people desire to be drawn together. Lodestones are gendered - male, female, and even transgendered or "neutral" stones - and you could work a pair of stones in many ways. An example would be to procure one stone for you, one stone for your friend, charge them and "baptise" them in your names, and then you keep her/his stone and s/he keeps your stone.
If you Google "Lodestone spells" i'm sure you can read and research the articles and spells found online, and with some creativity you can craft a friendship spell accordingly. I have a lot of information about Lodestones on my blog along with pictures and instructions on how to work them. If you go to my profile, click on the link next to "Website" and you'll find my blog. Good luck!