There are two ways to make a left turn. Walk your bike across. Pass on the left like other vehicles. Assume that other drivers don't see you until you are sure that they do. Eye contact is important with any driver which might pose a threat to your safety.
Some riders use rear-view mirrors, but still look before turning.
Cross railroad tracks at right angles. You may not stop in time if you brake one-handed. Allow extra distance for stopping in the rain, since brakes are less efficient when wet. Only ride with two prople on tandem bikes designed with two handlebars and two seats. Adjust your bike to fit you and keep it working properly.