According to Planned Parenthood:

Each year, 2 out of 100 women whose partners use condoms will become pregnant if they always use condoms correctly.

Each year, 15 out of 100 women whose partners use condoms will become pregnant if they don't always use condoms correctly.

This just proves how important correct condom use is. Not only for protection against unwanted pregnancy but protection against Sexually Transmitted Infections (STIs). There are many condom options out there. Visit: http://hubpages.com/hub/Barrier-Methods-of-Birth-Control to check 'em out!

Something very important is for both parties to insist on wearing them. Don't take "No" "I'm allergic" or "It won't fit" as an answer!

This should be an obvious first step, but obviously important. There is a four letter word called rape.

Fold the condom over onto itself. There should be a pocket of air inside the condom package. If there isn't grab a new one. This means that the condom has been punctured or damaged in some way.

Check for the expiration date on the condom package. This isn't easy to find in the dark. Its a good idea to check the whole box at the beginning and then you know you're good to go until let's say 2013. Do not use an expired condom! The latex has a shelf life!

Open the package carefully. Not with your teeth!! It may look sexy (I personally don't think so) but you could possibly damage the condom. Slide the condom over inside the package and rip down the side. 

After removing the condom from the package place it in your hand right-side up. The condom should look like a little sombrero. If it doesn't look like a sombrero it is upside-down. If you have the sombrero then it's FiEsTa time!

Pinch the tip of the condom. Why is this important?? Ejaculate needs somewhere to go. Without pinching the tip you're putting the condom at risk for busting. Ejaculate leaves the penis at over 25 miles per hour. That's faster than a school zone! 

While keeping the tip pinched the entire time, place the condom on top of the head of the penis and roll down to the base. Make sure there are no air bubbles throughout the condom. 

After intercourse hold the base of the condom before pulling out. Then take the condom off carefully without spilling the contents. You can tie the condom in a knot, tie it in a bow, whatever you want!

Wrap the condom in a tissue. Throw the condom away in the bottom of a trash can. Do not flush it down the toilet. It can clog it! Make sure it is at the bottom of the trash can because pets like latex! 

Check out all the different types of Condoms in my hub Condoms Condoms Everywhere!