A common mistake of novice bowlers is refusing to adjust. You can throw six strikes in a row and be bowling the game of your life, but that same throw won't necessarily hit number seven or eight. If you wish to have higher scores, (games & series) moving and minor (sometimes major) adjustments are needed.
Most experienced or high skilled bowlers take this into consideration every time they lace up their bowling shoes.
Read your lane conditions, adjust to them and execute. Here are a few tips:
One of the easiest first moves is moving your feet left or right to catch up with your shot. this applies to both righties and lefty's. If your release feels good, your speed is good just catch up to your shot with by moving your feet. Simply put, if you're missing left, move your feet left. If you're missing right, move your feet right. How much you move depends on how much you need to catch up to your miss.
Forward or Backward
The strategy behind moving forward or backward is the time it takes the ball to get to the pins. If you start forward from your normal position, the gets to the pins faster. If you step backward from your normal position the ball takes longer to get to the pins. A little trial and error until you get your desired results is usually the case.
Sometimes, there is no avoiding the fact you have to speed up your shot or slow it down due to the lane conditions. Slower speeds dictate more hook and delivering the ball faster will provide less hook. Adjusting your speed might be necessary when a lateral move isn't quite cutting it.
When all else fails, try a different ball. After All, if you have multiple balls on hand, that's why you brought them, right?
Good luck on the lanes!