The biggest piece of advice I can give to any author or writer anywhere, including myself, is this:
You are NOT in a race. This isn't about who gets published first, who writes the most, who has the most readers, who has the most sales. Honestly, it isn't. If you find yourself getting caught in the trap of, "So-and-so is doing really well - I need to step up my work and catch up," then know that the only reward for that sort of thinking is misery, burn-out, and more jealousy.
If you aren't happy where you are right now, what makes you think you'll be happy with just a little bit more?
How to convince people, though, that what they're doing--what they're capable of--is enough? That their honest effort, even if it isn't as much as someone else's, is what counts?
You must measure hustle, not sales. The effort you are putting into your work NOW is what is most important. Stop thinking about how everyone else is doing! You'll never be happy if you're constantly in competition with them.
The satisfaction you feel when you look back on a month of honest effort is something to journal about. And make sure you do, because those journal entries will become words of strength when you're struggling.
Getting off of my soap box. :-)
Oh, one last thought: slow and steady wins the race. Don't act like the hare; be the tortoise. :-)