Sidewalk surfing is just a fancy term for skateboarding. To become adept, you have to practice regularly to develop the proper riding mechanics including balance and coordination.
For beginners, the first step is to pick out a suitable skateboard. If possible, get a feel for different types of boards. Generally, you want to select a board that is fairly easy for you to maneuver for your weight and body size. This is especially the case if you plan on vertical riding and performing tricks. Experiment with board decks of varying lengths and widths until you find one that is fairly easy for you to handle.
When starting out, look for a wide open area with a smooth and even surface on which to practice. Focus on the fundamentals before moving onto the fancy tricks. The first step is to acquire your balance, so you are able to safely ride with both feet on the board while it’s in motion. Begin with one foot on the board and push off the ground with the other to get it moving.
Once you are able to ride in a straight line and turn and maintain balance on a moving board, move onto more advanced techniques, such as riding on ledges and vertical ramps.