Step 1:
Get a square paper. Fold it half and diagonally, till you get creased lines as above.

Step 2:
Creased lines will make it easier to fold. Fold the paper into a triangle

  
Step 3:
Fold point A inwards, to point B. You will get similar as the second picture.

  
Step 4:
Fold over flap A to point B, and you will get something like the second picture. Repeat step 3 for the right side.

  
Step 5:
You will get a diamond shape after folding both sides. Pull flap A downwards, to point B and fold in.

Step 6:
Now, you will get similar as the picture. Repeat step 5 for the back.

  
Step 7:
Fold flap A to B, and result similar to second picture. Repeat step 7 on the right, and the left and right behind.

Step 8:
You will now get similar as the picture above. Take flap A, fold it side, upwards. Do the same for flap B.

Step 9:
Flap A or B, bend the edge a little so it looks like the head.

Step 10:
Pull open both wings. You now have a paper crane.