Create a checklist for your pre-shot, set-up and approach.
I suggest your pre-shot routine contain: (as you no doubt do now) a mental review of the last shot on a particular lane (specifically, what did the ball do on this right lane (or left lane)), were you satisfied with the reaction and how you threw the ball, do you need to make a small adjustment, which ball will be thrown and can you picture, in your mind, the path through your target to the pocket? Next, pick up the ball you've chosen and wipe it free of oil and obvious dirt. Take a deep breath, exhale.
Whether your pre-shot or set-up contains putting your hand in the ball, do it. Feel the grip, is it FREE of grip pressure? No change in tightness of the holes, not experiencing any swelling, stickiness or slickness? Proceed to your set-up. Return to the starting point on the approach that gives you the best opportunity to roll the ball on the path you've chosen. Get into your stance, take a deep breath, exhale, feel some flex in the knees, observe the correct distance between your shoes (one or two boards, a couple, always see exactly the same distance). Make sure your feet, therefore your body, is aimed to allow the swing path you plan for your arm and the ball. Get the ball positioned (hand under, to the side, whatever), as you take another deep breath. As you exhale, relax then move into your first step.
You've started your approach, all the practice and league games have taught your body to throw a bowling ball, let your body do the job you've taught it. Micro managing any part of your approach begs for glitches, this is the time for execution not planning or readjustment.
Focus on your target and see the ball pass through (over) it. Look down at your footwork, is your slide foot at the point you planned (expected), are you in balance? Opposite foot up or on the ground? What is normal for you? If you put the ball on the target, executed the shot as planned, checked and your slide was on the money, look up, because the ball is hitting the pocket just the way you wanted. X. Now, this is bowling, not one shot perfection like golf, get up and do it again, and again, and again....