You can use Scotchgard waterproof spray to waterproof a tent as well as boots, jackets, tarps, and other outdoor gear. Follow the instructions on the side and remember to do it outside. You can find plenty of tent waterproofing products from sprays to liquids to brush on, seam sealants, patch kits, tape, and more. In general, the more you pay, the better the product, but you can also take a look at reviews to see which one is best. One key thing to remember is to make sure your tent is dry before stowing it. After you've sprayed, brushed, or sealed your tent, give it a full 24h to ensure all the waterproofing has fully soaked in and dried. Waterproofing your tent is a quick, easy job that pays off hugely. An hour or two of prep will ensure a whole season of dry, cosy nights enjoying the Great Outdoors.