All you really need to know you learned in kindergarten. Share everything; play fair; use only adorable vegan paper products. Wow, what kindergarten did you go to? Okay, so most of us learn that last one later in life. But Little Otsu’s new location in the Mission is chockful of to-do books, calendars, greeting cards, and stationery that’ll take you back to simpler days. Manage your time with a dreamy Aquatic Adventure weekly planner by illustrator Allison Cole or take a tip on efficiency with a three-in-one book by artist Lart Cognac Berliner — equal parts to-do list, sketchbook, and lined pages with instructions on the back cover for turning used to-do lists into origami. Or try Pee Mail, stationery on which a cheeky child, um, “writes” hello in the snow. The store also carries checkbook covers made from patterned fabrics, Kate Sutton gift tag sets, and sweatshop-free tees with limited-edition doodles by graphic artists like Lilli Carré and Martine Workman. So once you’ve got that lesson down, you can move on to nap time. Little Otsu, 849 Valencia Street, between 19th and 20th Streets (415-255-7900 or littleotsu.com).