Having bought your kayak, wetsuit and PFD, you'll be keen to get out, but there is one very important technique you need to practice before paddling out to sea, the Self Rescue.
Ideally on a warm day with a calm sea, or a sheltered bay. With another paddler on hand or a person on shore watching your progress, position your kayak so that you are just out of your depth and jump into the sea, cold isn't it!
Swim alongside your kayak and position yourself at the mid point of the cockpit, place both hands on the gunwale at shoulder width apart, bring the kayak close to your chest and allow your feet to float behind you. Pull your upper body across the gunwale and into the centre of the kayak kicking with your feet will help. Your belly button should be about centre of the cockpit. Roll over so that your bottom is in the seat, sit up and swing your legs back into the footwell.
Check your surroundings, if it's safe take a breather, if not paddle out of danger and take a rest.
Unlike a canoe your are less likely to roll in a Sit-On-Top Kayak, if this does occur you will need to flip the kayak up the right way. To do this position yourself in the middle of the kayak, reach over to the opposite side of the up turned kayak and grab the side, bring your knees up to your chest and press down on the nearside of the hull, lean backwards and the kayak will turn back over, you may get a bang on the legs but nothing to worry about. Time now to use the self rescue technique as described above.
If you do fall in remember to keep a tight grip on the paddle, this should be leashed to your kayak and is your safety line. The only time I would advise letting go of my paddle is in the surf zone (but only if this does not endanger any other water users), the force of the waves can cause the kayak to be catapulted back towards your head/face, best to swim in after it. Whilst on this point, never attempt to return to shore through surf if there is anyone in the water between you and the beach.