I may have sussed out the secret the making submissions:
Always keep at least one ball in the air.
With at least one poem "out there", you can stay optimistic. No need to dwell on the rejection received, the competition not won (or placed, or honourably mentioned)... If you've still got a ball in the air, you focus on that one.
And juggling requires momentum, too. And momentum is good, because then, you don't get stuck. You just keep printing out pages, licking stamps, mailing packets. The waiting is hard, but hope is better than nothing.
I've got three submissions out now -- three different packs of poems. One was to a competition. Scratch that one off the list. The second will take at least three months to answer; par for the course, I can live with that. The third one I should hear about any day now. You never know but fingers crossed, it may be good news.