It's easy to think that everyone is publishing more than you are, and receiving far fewer rejections. Even experienced researchers feel some apprehension upon receipt of referees' comments and the decisions that journal editors make. Little wonder then that PhD researchers would also feel the same apprehension. And the same intense disappointment when the journal editor's response begins "I regret to inform you...".
I re-discovered an old paper about "Publication rejection among ecologists" by Phillip Cassey and Tim Blackburn. It asked successful ecologists (or at least those who had published a lot) about their experiences of rejection. Overall, the 61 respondents had experienced rejection of their papers - about a quarter of their combined total of 2907 publications (a prolific bunch...) had been rejected at least once. Their take-home message: if at first you don't succeed, try try again.
My very first submission to a journal was a co-authored manuscript with my PhD supervisor and a postdoc. It received glowing reviews, with one of the reviewers complimenting our work and recommending that it should be published without any changes. (Stay with me: I'm not bragging and will get my come-uppance...). The postdoc told me to frame the review. (Now I understand why - it took another fifteen years before I saw another review like it). My next (also co-authored) manuscript was submitted soon after. The first referee began their review by saying "I can't believe these people claim to be ecologists..."
In their paper, Cassey and Blackburn emphasised that "publication success and manuscript rejection are not strangers".
Thus, it seems a thick hide is another skill to develop. But how can PhD researchers improve their ability to address reviewers' comments and to cope with rejections? One way to manage your expectations about the refereeing process is to discuss your supervisor's previous reviews of their own work - they may even be willing to share some of these with you on a confidential basis. Other PhD researchers in your group may also be willing to share their reviews with you. And on the day that you do get a rejection, remember that you are in good company. Put away the reviews for a few days, let the dust settle, discuss with your supervisor and decide on the next action.
Update: another paper highlighting the widespread rejection of submissions, followed by their subsequent acceptance. For another quite sophisticated example of rejection rates and impact factors in ecology journals see this paper.
PhD Skill: persevere with the publication process.