Contact friends in the destination country. This is the fastest way to find a sponsor because individuals in most countries have the right to formally invite you to the country. Check the immigration legislation and the requirements for an invitation letter because they vary greatly between countries.
Ask for sponsorship from your hotel. Certain countries, such as Russia and the United Arab Emirates, require a letter from your hotel to confirm where you will be staying. This way, your hotel can act as your sponsor in individual travels.
Book your whole itinerary from a travel agency and ask it to sponsor you. Travel agencies usually state clearly whether they are able to sponsor travelers who need a visa.
Request an invitation letter from a host from hospitality networks. Couchsurfing (couchsurfing.org) and Hospitality Club (hospitalityclub.org) are the largest of such networks. Your host can either write a formal invitation or just allow you to give his details to the authorities.
Ask a company, business or trade organization to sponsor you if you are a business traveler. Business visas are issued to short-term business visitors who are not ordinary tourists or prospective permanent workers in the country.