As the name suggests, Spanish/Mediterranean/Stucco homes are influenced by the region in its descriptive. This ranges from older homes with small windows and large doors topped by arch windows, to new-style Mediterranean homes that have larger windows.
Arch windows complement very well with the lines and pattern of Spanish/Mediterranean/Stucco style homes. Grid patterns can be used to create the illusion of multiple panes. French doors --- either swing or sliding ---- are recommended to help maintain integrity of the architectural style.