Before departure, please contact corresponding institutions (visa centers of destination/connection countries) for the:
need of a transit visa (depends on the connection airport);
possibility to leave the precincts of the airport during connection (depends on your visa);
need to take the baggage or its automatic transfer to the next flight (depends on the carrier, duration of connection and other factors);
provision of hotel and catering by the airline company during long connections;
need to check in during each connection or only a single check-in on the first segment of flight.
Please note that for technical reasons, some airports are closed during certain hours. In that case, you will need a transit (or other) visa of such country. Please look for such information on the airport's site or at consulates of the corresponding countries.