Set yourself up for success by choosing a project of manageable size that you can accomplish within the given time with the resources you have. Don't demand more of yourself than you can spare.
Allow yourself to be imperfect. Don't stress yourself out if the final product is too.
Take care of yourself. Give yourself breaks, drink fluids, and don't skip meals in work binges
When looking at others' submissions, don't let the critical part of your mind use the work of others to beat yourself up. If you see something particularly creative, clever, beautiful, or that seems to have taken a lot of work, enjoy it and be inspired by it. Do not devalue how you feel about your work by comparison. The work you created is what you were able to give at this time to that idea. It does not preclude you from doing more impressive work later, and others having more resources (time, creative energy, artistic ability, etc) that they can give right now doesn't mean you never can, or that what you did means less.
