The blade outline is what the blade looks like straight on. There are two types of blade outlines, symmetrical, and asymmetrical. Typically symmetrical blades are designed for whitewater while the asymmetrical blades are more suited for sea kayaking and flat water.
The lengthwise curve is the curve of the paddle when looking at the paddles edge. Most beginner paddles are flat with little to no curve. This offers more forgiveness in the paddle stroke. However, you do lose some efficiency since there is less friction between the water and blade.
The cross section is what the blade would look like if you cut the tip off the blade and looked at the cut edge. There are 4 typical styles of cross sections. They are, flat, spoon, dihedral, and wing blades. For beginners flat, and dihedral blades are best. They offer forgiveness that the other two do not. Spoons and wings provide more power, but are harder to control and require a bit more experience to paddle.
Finally you need some safety gear. Kayaks are not heavily regulated by the USCG and require only a few things. First, you are required to have your PFD onboard and accessible. However, I would recommend wearing the PFD anytime you paddle. In the event that you capsize and are floating free in the water, you would be well served to already have your PFD on. You never know when a current may pull you away from your boat and if your PFD is safely stored on your boat, it is going to do you no good if you are separated from your vessel. Second, you are required to carry a signaling device. This can be a mirror or some form of light. Third, you need an audible alert. This can be an air horn or a whistle or anything that can emit a loud sound on command. Bass Pro shop sells a great little whistle for about $5 that has a Signaling Mirror, a Compass, a Whistle, and a dry container all combined. This really covers what you are required to have by Coast Guard Regulation.
That can't be all right? Well no. Just because it is not required there are other things that you should carry for safety. A paddle leash would be a good idea so that your paddle will stay with your kayak at all times. These are very simple devices that are made out of various materials and cost very little to acquire. You can even make one out of items you may have sitting around your house. The important thing is that the leash should be long enough to not impede you paddling but short enough to keep the paddle close by when it becomes separated from you and the kayak. You should also consider a safety knife. A safety knife should be kept with you at all times. I keep mine in one of the pockets of my PFD. This is important in the event that you capsize. When capsized, you may find yourself tangled in your decking rope, paddle leash, gear leashes, or even some underwater obstacle. You need a knife available to cut you free, but at the same time you need one that will not cause you more harm. A safety knife is designed with a blunt tip to protect you, yet a serrated blade to help cut through whatever is binding you. SOLAS tape is useful in making your kayak visible from a distance. SOLAS stands for Survival Of Life At Sea. This is a highly reflective tape. I have about 6 strips of SOLAS tape across the hull of my boat above the water line as well as a couple of strips wrapped around my flag/light pole. Speaking of the flag/light pole, if you are going to paddle at night, you need to have a light available to signal your presence. You don't have to have the light on at all times, but if I am paddling, I prefer to have at least one stern light going. I have two for my kayak. One really bright light about a foot off my deck, and one about 3'-3.5' up on a pole. I leave these on at all times and keep a head lamp ready in the event that I need it.
Yak Attack makes a product called the VISIPOLE which nicely combines, the Pole, SOLAS Tape, and Stern Light together. They are virtually indestructible and can be purchased at www.yakattack.us or through any of their authorized retailers. No I don't get a kick back for saying this, or any compensation. They just make a really great product. The one thing that the photo does not show is a signal flag. It is best to get a highly visible flag for daytime paddling. When mounting a light (if you are not buying a prefabricated one), make sure that you mount it on a pole high enough for most boaters to easily see. Keep in mind that when paddling in rougher conditions, you may find that the waves can hide you momentarily from view so you want to give yourself the best chance at being visible.
A commonly overlooked piece of safety gear is dry storage containers or bags. When out on the water, it is advisable to keep a set of dry clothing in the event that you capsize. You can get dry bags at most outdoors stores or sporting goods stores. You should also carry at the very least a cell phone and you most likely would want to keep that in a dry box or bag. You will find many other things that you may wish to bring that would be best stored in a dry compartment.
This list is by no means complete but does give a general look at things you should bring for safety. Other items include signal flares, power bars, drinks, rain/dry gear and the list goes on and on.
Yak Attack makes a product called the VISIPOLE which nicely combines, the Pole, SOLAS Tape, and Stern Light together. They are virtually indestructible and can be purchased at www.yakattack.us or through any of their authorized retailers. No I don't get a kick back for saying this, or any compensation. They just make a really great product. The one thing that the photo does not show is a signal flag. It is best to get a highly visible flag for daytime paddling. When mounting a light (if you are not buying a prefabricated one), make sure that you mount it on a pole high enough for most boaters to easily see. Keep in mind that when paddling in rougher conditions, you may find that the waves can hide you momentarily from view so you want to give yourself the best chance at being visible. 
This list is by no means complete but does give a general look at things you should bring for safety. Other items include signal flares, power bars, drinks, rain/dry gear and the list goes on and on.
