A great deal of surface street congestion in LA's commercial districts is caused by drivers circling the block in search of free or cheap on-street parking. This happens despite the fact that spaces are often available within a few minutes' walk, either on a less busy street or in a private garage. The result is that commuters are often held up by local traffic that isn't even headed anywhere in particular. The City should institute a number of reforms to fix the problem.
-Change the way meters and City garages are priced to respond to demand, so that people will be discouraged from parking in the busiest (and thus priciest) locations for long periods. Vary the price block by block, and hour by hour. At all times, the goal should be to have one or two vacant spaces on each block, so that a convenient space is always available at the moment someone needs it and spaces do not sit empty for long periods due to being overpriced.
-Make it easier for people to find out about parking rates and availability before they arrive, by means of a website and smartphone app. This will eliminate the need to cruise around the block, and will clue people in to relatively cheap parking near their destination they might not otherwise know about.
-Use the revenues generated from the new pricing scheme to create a parking benefit district that will spend the money on improvements and services that benefit the businesses and residents in the area. The district created in Old Pasadena has funded street cleaning, landscaping and other benefits that have aided commercial revitalization and removed political obstacles to the installation of meters in an area where parking was previously free.
-See Donald Shoup's The High Cost of Free Parking for more recommendations. Also, San Francisco's SFPark program is pretty rad at implementing everything I just described.