What kind of a person are you? Is your glass half full or is it half empty? Do you have a generally positive outlook with your writing or are you more pessimistic? Our attitude to our writing and, indeed, our life in general is a big indicator as to how our lives and writing might go. If we think that we can't write and let every rejection prove that, then we become a self fulfilling prophecy. We think we can't do it so therefore we don't do it. I suspet that most of us live somewhere in the middle of the two.
If, however, we adapt the more positive mindset of we can do it and we have done it so we can, therefore, do it again, we become more productive and each rejection that comes our way loses its sting somewhat because we have more work out there that may well be an acceptance.
Simon Whaley's www.simonwhaley.co.uk marvellous book the Positively Productive Writer goes into more detail about how being positive can help you to be published so I'd recommend this book if you haven't yet read it. I'm also featured (a tiny bit) in it where Simon takes you through my little TV experiment. Simon and I also attend the same writers' group where positivity positively pings round the room every time we meet! So it does work!
So next time you're feeling less than enthusiastic about your writing career, where those around you seem to be having more success than you, or you have a mental block on how to move forward, ask yourself this: what would be your biggest regret should something prevent you from writing ever again? What would you wish you had finished? What would you regret not having the chance to have tried to have got published? Sobering, but motivating and positive thought.