credits to austinkleon.com:
The letters aren’t really letters, they’re diaries. Rilke saw himself in Kappus, and so they’re written from Rilke to Rilke—both to his past and his present. They begin with a description of Rilke’s current setting (various cities across Europe) and continue into the subject of how to live and how to create. Each is a map of where he’s been and where he needs to go.
There’s so much to take away from the ten letters, but here’s a short-list of questions a young writer might ask, with Rilke’s responses.
Is my stuff any good? Am I good enough to really make it as writer?[You're asking the wrong questions!] There is only one thing you should do. Go into yourself. Find out the reason that commands you to write; see whether it has spread its roots into the very depths of your heart; confess to yourself whether you would have to die if you were forbidden to write. This most of all: ask yourself in the most silent hour of your night: must I write? Dig into yourself for a deep answer. And if this answer rings out in assent, if you meet this solemn question with a strong, simple “I must,” then build your life in accordance with this necessity….
…But after this descent into yourself and into your solitude, perhaps you will have to renounce becoming a poet (if, as I have said, one feels one could live without writing, then one shouldn’t write at all). Nevertheless, even then, this self-searching that I as of you will not have been for nothing. Your life will still find its own paths from there, and that they may be good, rich, and wide is what I wish for you, more than I can say.
What should I write about?
Write about what your everyday life offers you; describe your sorrows and desires, the thoughts that pass through your mind and your belief in some kind of beauty - describe all these with heartfelt, silent, humble sincerity and, when you express yourself, use the Things around you, the images from your dreams, and the objects that you remember. If your everyday life seems poor, don’t blame it; blame yourself; admit to yourself that you are not enough of a poet to call forth its riches; because for the creator there is not poverty and no poor, indifferent place. And even if you found yourself in some prison, whose walls let in none of the world’s sounds - wouldn’t you still have your childhood, that jewel beyond all price, that treasure house of memories?