As a writer, the most common (and maybe most valuable) advice received is: develop a tough skin and learn to take rejection well.
I've received my fair share of rejection through the years, and in fact, it became a point of pride that I learned to take it well. I got so good at receiving rejections that I'd write thank you letters to agents and publishers, thanking them for having rejected me.
Thank you so much for your time and the consideration of my novel. I thank you profusely for having rejected me and I hope to one day submit another story to you for future rejection.
I became so skilled and eloquent that Hallmark offered me a gig writing for them. Unfortunately, I had to turn them down because I am unable to confine my thank you efforts to just one line.
Eventually, I became so accustomed to rejections that I didn't know how to react when The Wild Rose Press offered me my first publishing contract for A Cat's Tale. I actually emailed Angela Anderson to be sure there had not been an egregious mistake.
Thank you so much for your time and consideration of my novel. I thank you profusely for having
accepted me, but I feel compelled to allow you the opportunity to retract your
offer in the event that it was sent in error.