Getting more light into your home cuts on energy costs, but also can bring one closer to the outdoors. Like windows on the side of the house makes you a passive observer, skylights allows you to check the skies above. Placement is critical in the sense that skylights would let too much light in which would heat up a home (not bad in winter, not so cool in summer), but there is also the problem that high intensity sunlight can fade carpets and other fabrics as well photos over time.  A southerly and west view lets in the most intense sunlight, however, a northern and eastern view will let almost as much light in without the overkill lumens. If you cannot avoid it, then get a window which is tinted to soften the sun's effects.

Big box home centers usually carry the 16" to 4' lengths and 2' to 6' widths on special order, however, they can also be custom (more expensive) made. There are some models with "self-flashing", however it is believed they are more prone to leaks. Best to have a custom installation. The good news is there are skylights which are tied into a thermostat to open electrically as temperature climbs as well close as things cool down. Sensors that feel the first sense of moisture will close them. The one drawback is if there is a power failure, then the windows will not function requiring manual closing or opening.

There are also "curb style" skylights which needs the installation of flashing and is mounted over a wood frame. To install, a 2"x4" or 2"x6" frame is constructed making sure there is a half inch difference on the outside as opposed to the inside of the opening, allowing the window to fit over both the curb and flashing. Once the curb is nailed, square it with a framing square. Tack two pieces of light wood across the diagonal corners, holding it in position. A simple way is to use regular rafters as opposed to jack rafters. When the roof is sheathed, leave an opening for the skylight flashing with the inside edge of the framed opening. Set curb over the the hole in sheathing when ready to install roofing. Make sure the curb is centered, square and on an even plane. Toenail the curb to the rafters by nailing through the decking. A sheet metal shop can cut the flashing for you. Install flashing with the roofing. The first piece of flashing should overlap with the base flashing, then slide it beneath the the second course of shingles, embedding it in roofing cement. Nail it to the curb along the top edge. Continue in this style until you reach the top. Fit head flashing over top curb, embed in roofing cement and nail. Further spread roofing cement over top and sides of apron, extending over roof deck, nailing next course of roof shingles, setting each shingle edge in roofing cement. Apply a bead, caulk or cushioned waterproof weather stripping to the top edge of the curb. Drop skylight over curb and flashing. Attach skylight to curb using galvanized or aluminum screw nails with neoprene washers, attaching curb through factory cut holes. Screw skylight in temporarily until interior is secured. Next, screw firmly into place and dab with roofing cement. Check instructions for self-flashing skylights.