Start at the Mozartplatz, not just to make a pit stop at the tourist information office, but to sweeten your tour with a few Mozartkugeln from the nearby chocolate manufacturers Fürst. Flower-bedecked cafés beckon, as does the palatial Residenz, home to the great prince-archbishops and the center of Baroque Salzburg. Nearby is the Dom, Salzburg's grand 17th-century cathedral. Across the Domplatz is the Francescan church, the Franziskanerkirche. A bit to the south is the Romanesque-turned-Rococo Stiftkirche St. Peter, where, under the cliffs, you'll find the famous Petersfriedhof -- St. Peter's Cemetery, whose wrought-iron grills and Baroque vaults shelter the final resting place of Mozart's sister and much of Old Salzburg. Take the Festungsbahn cable car (it's just behind the cathedral) up to the Fortress Hohensalzburg -- the majestic castle atop the Mönchsberg peak that overlooks the city. Enjoy a rest at the Stadt Alm restaurant or picnic in a quiet corner. Descend back to the city via the Mönchsberg express elevators.
Head over to the Pferdeschwemme -- the Baroque horse trough that is a somewhat bewildering tribute to the equine race -- then over to the Getreidegasse. In this venerable merchant's quarter, posh shops set in pastel-covered town houses announce their wares through the overhanging wrought-iron scroll signs, and some of the houses have hidden courtyards set with timber-lined balconies. Next up is the most famous address in town: No. 9 Getreidegasse -- Mozarts Geburtshaus, the birthplace of Mozart. After paying your respects, head over to the Alter Markt to welcome twilight with a Kaffee mit Schlag (coffee with whipped cream) at Café Tomaselli.
With three days, you can explore the Altstadt -- the Old City -- and the New Town as described in the two walking tours below. Try to catch an evening concert -- perhaps of Mozart's music. For your third day, try one of four options: book a Sound of Music tour, then, in the afternoon, take a ride up the Untersberg; or opt for a boat trip along the Salzach river south to the 17th-century Hellbrunn Palace with its mischievous water fountains; or take an excursion to the the picture-book towns of the Salzkammergut.
A fourth idea is to walk for about two hours over the Mönchsberg, starting in the south at the Nonnberg Convent and continuing on to the Richterhöhe to enjoy the southwestern area of the city. Above the Siegmundstor, the tunnel through the mountain, there is a nice belvedere to take in a city view. But the most fascinating view is from the terrace in front of the new Museum der Moderne, which you reach after passing the old fortifications from the 15th century. Continue on to the Augustinerbrä, the large beer cellar at the northern end of the hill for some of the best brews and conviviality in town.