All major airlines fly to Venice Marco Polo Airport (airport code: VCE). Which is very close to the city center and it takes only 30 minutes to reach the city by express bus (Information and timetable can be found here).
You can also take a ferry served by Alilaguna or a water taxi from the airport. You can find all information and prices here.
Venice is on a major rail line served by local, regional and high-speed trains. There are two train stations in Venice: "Venezia - Mestre" and "Venezia - Stazione Santa Lucia". The former is on the Venice mainland, then it is better to stay on the train and arrive at Santa Lucia station. In case Mestre is the last stop of the train, you can always take a shuttle train that goes every few minutes across the lagoon into Venice.
You can easily get to Venice by car through motorway (A4 from Trieste and Turin, A27 from Belluno, and A13 from Bologna) and road links (SS309 Romea from the Adriatic coast, SS14 from Trieste, SS13 from Treviso, SS11 from Padua). Once you have reached the lagoon take the Ponte della Libertà, the bridge that literally links Venice to the mainland. If you follow the signs to Venice, youll find yourself in Piazzale Roma, which is as far you as you can go by car. The following parking areas are available: Autorimessa Comunale, Garage San Marco and S. Andrea Tronchetto.
You can reach Lido directly with Alilaguna public boat service from Marco Polo Airport. The boats leave every half an hour. The trip will take you about 50 minutes. Tickets can be purchased at the boat terminal.