There are many things you can do to improve your bowling game away from the lanes including practicing your steps to visualizing consistent strikes.
The First Step
Find a place with a vinyl, tile or hardwood floor similar to the bowling lane.
Make a "T" with tape to mark your starting position.
Place your toes at the top of the "T".
Figure out your ideal first step, and mark that spot on the stem of the "T".
Practice your first step while visualizing bowling a strike.
Repeat your ideal first step so that it is exactly the same everytime. You shouldn't have to look down at your marker to know where to step.
Understand that a good "first step" is the key to good approach. A good consistent first step equals a good consistent approach.
The Back Swing
Stand in your normal, comfortable, start position without a ball.
Visualize the lane in front of you and fix your gaze on a specific spot in your imaginary lane.
Swing your bowling arm back in a mock backswing.
Do fifty to one hundred of these mock backswings.
Realize this process will help you groove out your backswing so that the motion of your arm becomes very familiar.
Make sure your thumb is pointing down at the top of your backswing.
Visualize bowling a strike with each swing.