Passive solar heating system are designed to capture the natural heat from the sun to help heat the home. By placing more windows on the south side of the home will allow more sun light to enter the home. You want to let more sunlight into the home during the winter. And very little during the summer, so that the home is not get too hot.
Installing lots of skylight is not recommended. Because it will make the home difficult to cool during summer months. During the summer the sun passes more directly above the home, and if their is a skylight the sun will shine directly into the home.
You can see in this illustration that eave blocks the sun from entering the home during summertime. Because the sun is at a higher angle, and shines more strait down. But during winter the sun is much lower on the horizon. As you can see the sun now comes in the window to warm the house.
On many well designed passive solar homes the number of windows on the north side of the home are kept to a minimum. Since their will be no heat gain from these windows. Window area on the west sides of the home is minimized to help reduce over heating. While the south side of the house will have a much larger window area. This were most of the solar energy enters the home.
Their other issue also with interior temperature swings threw the day. To help moderate these temperature swings a heavy storage mass is used. This mass absorbs the heat during the day, and releases it during the night. This mass can be a tile, stone, or concrete floor. It also could be a interior wall. The more mass the wall or floor has, the more heat it can store.
It's also important to select a good quality window. So that you don't loose to much heat. Since windows allow more heat to escape threw them than a insulated wall.
When under going designing passive solar home it wise to consult with a architect that is familiar with passive solar heating. Since it is more difficult to correctly design a passive solar home.