The best pickleball shoes are court shoes with grip and tread designed for quick side-to-side movements. Tennis shoes are great for pickleball since they both demand similar movements on similar court surfaces. Running, walking and cross-training shoes are not good for pickleball because these shoes are designed for front-to-back motion.
If you're interested in what to wear to play pickleball, the easiest solution is to wear clothes similar to what you'd bring to the tennis court. A lightweight athletic tee, tank top or polo shirt will be just fine, along with shorts or a sport skirt. Wear a visor or hat, to keep the sun out of your eyes, or a headband to absorb sweat.
Pickleball has a few key differences from tennis. Pickleball paddles are smaller than tennis racquets, and a pickleball court is much smaller than a tennis court. The balls are different too — pickleballs are hollow and lightweight with holes in them, and they don't bounce as high as tennis balls. Pickleball is also usually played in doubles, not singles like tennis.