You must provide documents showing the purpose and condition of your stay. If you are visiting as a tourist, you must provide information detailing your plans for the visit. These may include a travel itinerary, hotel and flight booking, etc. You must also explain your purpose well at the interview with clear knowledge about your plans for the visit. You must show sufficient knowledge about any places you wish to visit, the duration of your stay, entry and departure dates, and why the Schengen country is your preferred tourist destination. You must provide your answers in a clear and coherent manner to assure the consulate that you have sound reasons for your visit.
If you visiting a family or friend, you must show that there is a genuine relationship between you and the person. Evidence may include phone records or other proof of social media communication. You must show adequate knowledge about the person including the nature of the relationship, the last time you met the person, how often you communicate, and information about the person’s work, family and other personal details.