For the interested person looking to upgrade their game on friendship I would recommend reading / listening to these resources to get you thinking about friendship:
The Four Loves – by CS Lewis. Either in the book for the full text, or the succincter audio version with his actual radio recording (available on DownPour or iTunes Audio)
I love listening to his beautiful English choice of words and old school speech. Reading the book of course is fantastic too.
And here the link to Harper Collins
Inside Out by Sarah Abell. It is essentially a review text for yourself how you are living all your relationships. Many questions inside to ponder on how you relate in particular to your family, i.e. spouse, parents and children.
The Friendship Formula by Kyler Shumway: While from the title it makes you cringe as yet one of the American style superficial books, it is actually based on deep experience of friendship and full of incredibly practical advice for people who want to be better friends. If you want to skip past the longwinded philosophical deliberations, it is the book for you.
How to relate well – Nicky and Sila Lee (a Christian Sermon from St. Pauls letter to the Corinthians – 30 min) – it obviously has a Christian background, which might be a no go for you, but it is the most succinct actionable ‘how to do relationships’ I have come across.
Unfortunately the 2010 relationship version has disappeared of the web, and the follow session is now super tailored for Christian couples. Still most of the points are the same: the 4 Ps of Friendship (Positivity, Proactivity, Patience, Peace) plus Purity (for romantic Christian couples, if that’s not you, feel free to roll your eyes, but the rest is too good to ignore.)
Vital Friends by Tom Rath: – the book is OK, and unfortunately incredibly sparse on research methodology employed, the total research seems to be based on no more than 1000 interviews in three batches. What is however very good is clarifying the roles friends can have for you, how they can be a friend to you, and that they have one or two roles, but don’t have to fulfil all eight.