When modelling the bowling pins, i used a cylinder and added edge loops where most of the sculpting would take place. From there i selected the line of vertexes and used the scale tool to slowly start creating the right form.
Using the front view was really helpful so that i knew i was selecting all the vertexes on that line.
Creating the top was slightly more tricky this included me using the extrude tool on the top edge, shape that using the scale tool and then repeating this process over again until i got an oval shape.
Creating the bowling ball was fairly straight forward i used sphere and then used the Boolean tool to create the finger holes. And here was pretty much have the bowling pins and ball complete.