Read. Read a variety of genres. Poetry, even if you are not a poet. Essay collections. History. Philosophy. Novels. Novels from different countries, different times. That's how I avoid writer's block. I am a voracious reader. I always, and I mean always, have a few books I am reading. This prompts ideas, questions, character issues, all of which help with my writing. That would be my suggestion for eliminating, or reducing the frequency of, writer's block.

I don't have writing prompts per se. I think about a question, often with philosophical undertones, and I wrestle with this question for weeks, even months, before I start writing about characters and their situations. Later I create a 'story' out of this miasma in my brain.

I didn't really receive much advice as a young writer, only because I did not seek it. I mostly learned by doing, and found my own way. Let me change the question a bit, and so be helpful. The most valuable advice I would give a young writer is to be critical of your own writing without being self-destructive. You need to develop as a writer, and what you need to develop is that internal judgement of when a story or essay is in good shape. You do that by reading constantly, and also by "killing your little darlings" and starting over again, in rewrites. But to keep this cycle productive, you need to avoid being self-destructive. I find that many young writers destroy their work without ever improving, or without ever learning what practically will improve their work. The quote is from Faulkner, but the advice is mine.