Frame your photos. Use matching or similar frames to create a sense of cohesiveness in the display. Instead of matching frames, you could also choose photos with a uniting quality, such as ones that are in black and white or ones that feature a theme like vacations or weddings.
Trace the shape of the frame onto a sheet of butcher paper. Mark on the paper where they should be hung so you will know where to make nail holes later. Cut out your shape and label with a name or number of the photo. This will allow you to get an accurate sense of proportion so you can estimate how they will look on your wall. Alternatively, arrange the framed photos on a flat surface to see how they will look when hung.
Tape your paper cutouts to the wall with painter's tape. This tape will not damage the wall, so you can take them down and rearrange your photos as needed. The way you hang the photos can set the tone of the design. For example, if the photos are all the same size, arranging them linearly will make the look clean and minimalistic. For a more eclectic, casual feel, try staggering the photos at different heights on a focus wall, such as over a sofa or in a long hallway.
Hammer nails into the wall according to your notes on the paper. Once the nail is in place, pull away the paper and mount your framed photo on the nail. Adjust as needed with a level.