The view to the Alhambra from the Mirador de San Nicolas provides an impression of the size of the palace complex, the massive walls and towers appear austere and powerful, nothing indicates that the interior houses a gem of Moorish architecture. And even when you stand in front of the entrance gate of the Nasrid Palaces - the heart of the Alhambra - you see only an inconspicuous façade. In contrast to European palaces, a sumptuous exterior is not characteristic for Moorish architecture. But that changes fundamentally as soon as you enter the interior: abundant wall decorations, inner courtyards with fountains and water basins, coloured tiles everywhere, elegant columns, filigree stucco decorations. Unfortunately, large parts of the Nasrid Palaces were destroyed after the Reconquista, e.g. to build the Palace of Charles V.
We visited the Alhambra in September 2016 and I agree with other reviewers that booking in advance is highly recommended. You can print your pre-booked tickets at one of the ticket machines without queuing. In summer, you have to choose between morning and afternoon visit and you have to select a time slot for the Nasrid Palaces. However, it is hardly possible to avoid the crowds, there are tourists all year round, probably less in the winter, but this is not the best time for a visit, at least for the Generalife garden, beside the Nasrid Palaces the second highlight at the Alhambra.
Alhambra and Generalife are well described elsewhere, so just a few remarks on the Albayzín, the oldest quarter in Granada. The above mentioned Mirador de San Nicolas is a must (the photo shows the view to a part of the Nasrid Palaces). I recommend a visit in the evening at sunset, and though you have to share the beautiful view with hundreds of tourists, it is an unforgettable experience. I liked the narrow streets and white-painted houses of the Albayzín. One gets lost inevitably, but that does not matter, sooner or later you will find the way downhill to the Carrera del Darro or the Plaza Nueva. There are several buildings that can be visited, the tourist information offers a combined ticket and a map with the locations. We visited three sites: the Banuelo (larger and more interesting than the baths of the Alhambra) and two palaces, the Casas del Chapiz with a beautiful garden and nice views to the Alhambra and the Palacio de Dar al-Horra. Unusual for Andalusia, these sites are opened all day without a siesta break.
For the evening, I recommend the restaurants and bars at the Plaza Aliatar or Plaza Larga, which are also popular with locals, or along the Carrera del Darro. Our favourite tapas bar was La Gran Taberna at Plaza Nueva, a traditional tapas bar open until late at night and perfect for a last drink.