Generally Greeks are not enthusiastic administrators so if you have good organisational skills and office experience this will be a plus. Villa housekeeping, cleaning, nursing, childcare, pool maintenance, gardening work, tourism, property/marketing positions are all possibilities, although not always advertised and getting your foot in the door as a foreigner may not be easy.
The best area for jobs is probably teaching English or other languages. You will certainly need to have at least a bachelor’s degree, and a teaching certificate such as a TEFL or TESL qualification will be a big advantage. These can be obtained through online courses, such as:
The following website is a good database for summer jobs in Greece: