There are many factors affecting the intention of choosing a destination which were widely validated. For example Push & pull factors (Crompton, 1979), Iso Ahola´s motivation model (Iso Ahola, 1982) + Educational, Relaxation, Ethnic & Sundry motives introduced by Lundberg (1971) & Shoemaker (1994), Climate, relaxation, adventure, personal, Educational (Bansala & Eiselt, 2004). You can select any of these factors and apply it according to the 'Theory of Planned Behavior' (as a research framework) to measure how they can be applied in travel. TPB is a broad concept that can be applied in many fields. Please read followings for further information:
Check for 5 As in tourism i.e. accessibility, accommodation, attractions, amenities, activities. These days affordability, advertisement is also coming in to the picture.
Factors affecting the intention of choosing a destination include; economic factor, accessibility, location, image, cost and attractiveness of amenities.