Another article that would help is here: http://onlinelibrary.wiley.com/doi/10.1111/j.1399-3054.1995.tb00983.x/pdf
This one has a specific section on chloroplast isolation. The general method is to centrifuge cells into a pellet. Wash them in buffer solutions to open up the cells and finally pass them through a sucrose gradient. Within a specific range 1.75-2.00M of sucrose is where high concentration of your chloroplasts will be found.