The syllabus states that candidates should be able to “describe and explain the growth of leisure facilities and tourism in an area selected for study”; and “demonstrate an understanding that the effects of a growth in tourism are generally positive and that careful management is needed if problems are to be avoided.”
Benidorm obviously provides a local model for us to use for a case study and is provided on this website in the extended Benidorm tourism case study on the main drop-down menu on the right. This study shows the development of Benidorm as a resort, but you need to consider also the advantages of tourism such as growth in income, employment opportunities, the development of infrastructure and facilities which may be used by the local population, the encouragement of other developments to take place in an area, cultural advantages, etc.
Also you must explore the disadvantages, which might include seasonal unemployment, under-use of facilities at certain times of the year, increased congestion, pollution, a shortage of services (e.g. the water problems), social/cultural problems, damage to the physical landscape, etc. (You can link to it directly from here. These resources are provided for both GCSE and A-level Geography, so some material may not be relevant: follow guidance on this.)