I recommend using the floor as the "wall" to test the arrangement prior to putting your pictures on the wall.
Follow these steps to do it right the first time.
1.
Determine the size of the wall space you wish to fill using a tape measure.
2.
Mark the same size space on your floor directly below the wall location.
Use coins to mark the four corners.
3.
Lay the picture frames on the floor space.
Change them around in different arrangements to see what looks best.
I recommend keeping the bottoms aligned.
The pictures should be at eye level for best viewing.
Select one picture as the focal point and arrange the others around it.
Place the pictures in a logical order or sequence if they tell some kind of story.
Perhaps if they are family photos you could arrange them by date.
I also recommend you not to place larger pictures on top of smaller pictures because it will make the arrangement seem unbalanced.
You should not place your pictures in direct sunlight or near a heating source as this will slowly damage your pictures.
4.
Once you've decided on your perfect arrangement turn the pictures over.
This permits you to see where the picture wires/hangers are located.
5.
On the wall you need to measure the exact locations for the picture hooks from right to left and top to bottom.
Hammer them firmly but gently in place.
If the wall is made of plaster you can prevent chipping by placing small pieces of self sticking tape at each location where picture hooks or nails will be inserted.