Throwing a house ball straight down the lane and knocking over a few pins has been great but if you want to really improve, you may need to change the ball you use and how you hold it if you want to see greater pin action, especially with carrying corner pins.
Changing the ball means stepping away from the house ball – those are the balls at the centers, which are made of plastic – and getting your own reactive or urethane ball. You’ll want to stop into your local pro shop for this, who will ask you about how you bowl and what your goals are. Equipment needs vary between the novice and pro bowler. Mention that you’re interested in learning to hook the ball and you’re ready to step up to something that will help.