1. Footwear: Although you can wear flip-flops or sneakers while kayaking, I do recommend some outdoor shoes especially made for water sports. These shown are Chacos I bought at REI. They are very complicated to get on (all of those straps are really just one loop that goes in and out of the shoe and around your foot!), but that means they are less likely to fall of your feet when kayaking (or if you fall in the water!).
2. Hat: You want to protect your face from the sun when you're on the water. I prefer baseball caps, but a sun hat or visor would do, too.
3. Sunscreen: If it's a sunny day, make sure to put sunscreen on! The sun will be shining on you for several hours, so it's almost like you're sunbathing!
4. Phone Charger: Yes, you can always leave your phone at home, but in our day-and-age, chances are you won't. But when you're in the great outdoors, it can be difficult to charge you phone. Not anymore! I just bought this Evolution on-the-go charger from Groupon. It works wonders! You just charge it using the USB cord it comes with (either connect it to a wall outlet or your computer), and once it's fully charged, you can use it wherever you want to power up your phone! You never have to worry about your phone dying again! That means you can take more photos and videos of your kayaking trip, and then tweet about it, too!