Summer’s been real, Mom, but it’s time to clean up our acts. How about asking celebrity stylist Sally Hershberger how to keep mini mops looking great through fall? Keep It Simple Classics like the crew cut and the surfer shag are always cool. For the crew cut, ask your stylist to use a No. 3 guard on a peanut clipper. Insist that shags be kept longer in front, so nobody looks like the fifth Beatle. Go for Goo Most boy cuts can be updated with product. For longer hair, try texturizing creams (Hershberger’s Wreck & Roll, Kiehl’s Cream with Silk Groom). For shorter styles, pomades such as Shu Uemura’s Shape Paste Sculpting Putty give shine and definition. Girly Do’s Add soft, long layers to straight hair for a sweet update without sacrificing the length needed for ponytails, buns, and twists. Bangs also update a girl’s cut and reduce styling time in the morning. Trim Time For a quick DIY bang trim, create a thin half-moon section at the hairline. Once you pick a safe length, start your fringe, working from the center out to ensure a straight line. Style with a round brush. Stock Up Keep lots of hair accessories (headbands, ponytail holders — Scüncis are perfect for sensitive heads), as they camouflage bad hair days and cut prep time for school in half. Now let’s see who gets snippy. Or go straight to the source at Sally Hershberger Downtown, 423 West 14th Street (212-206-8700 or sallyhershberger.com). PLAY Preschoolers Fall Fun Party What: A back-to-school send-off with live music, art projects, storytelling, and fun snacks. Why: Ring in the new year. When: Fri., 11 a.m.-1:30 p.m. Where: Brooklyn Children’s Museum, 145 Brooklyn Ave. (718-735-4400). SEE Claes Oldenburg at the Whitney What: Show gallerinas-in-training such kid-friendly sculptures as “Giant BLT” and “French Fries and Ketchup.” Why: It’s art for all ages. When: Thru Sept. 6. Where: Whitney Museum of American Art, 945 Madison Ave., at 75th St. (212-570-3600). MAKE Nature Crafts in Prospect Park What: Kids create toys, puppets, and more using all-natural and recycled materials. Why: Mother Nature makes masterpieces. When: Thru Dec. 20. Sat. & Sun., 1-3 p.m. Where: Prospect Park, Audubon Center, Lincoln Rd. & Ocean Ave. (718-287-3400).