Composition Shingles

Before starting a repair, locate replacement shingles of the same type, color, and size of the existing shingles.

On a warm day, lift the tab above the shingle that has been damaged and pry out the nails that hold the one you want to replace, as shown in the illustration at top left.
Snip off the top corners of the replacement and slide it up under the existing shingles, being careful not to tear the roofing felt. If you accidentally tear the felt, patch it with roofing cement.

Nail on the new shingle, placing the nails under the shingle above. Nail by hammering against a pry bar placed on the nail heads, as shown at bottom left.

While you're on the roof, check the roof flashing for corrosion or pinholes and repair with roofing cement (you may need to lift up a flap of shingles to get access to the flashing).