Keep the emails that make you smile. Every time you get a note that boosts your spirits, drop it in an Evernote folder, an email folder/label, or Google Doc. It will be nice to look back on them whenever you’re feeling down.*
Don’t throw away your to-do lists. They remind you of what you’ve accomplished, and can help you accurately discuss your work and not accidentally downplay your role and impact.
Express gratitude for yourself. Routinely expressing gratitude at the beginning and end of the day is a highly recommended mindfulness practice. Recently I’ve been taking it one step further by making sure I always recognize my gratitude for some part of myself—a personality trait, something I did that day, or even a part of my body. Generosity can and should be channeled inward, not just outward.