Not to say that I don't get in a funk every now and then, but here is what I do...
1) Plastic is the best investment I've made bowling in a long time. It allows you to throw the ball in a natural way without over-reacting on the dry you find out there. Besides $35 for a W/D + drilling will pay for itself many times over with bracket money...
2)I always tried crossing the middle arrow going completely cross-lane, but I was still missing more than I liked. So after some thought I figured out that the ball returns length in different houses were longer and made me throw kind of bound up. I figured with the ten-pin being the most difficult single-pin spare that I should toss it in my general comfort area since the above-mentioned W/D goes straight.
3) I line up at 28 (8 bds left of center) walk slightly towards the target and throw a slightly weaker than normal release over 14-15. The key for me is doing it without effort. Just roll the ball. It will hold. It won't over-react. Same speed.
4) It makes all the difference when you take the oil out of play with plastic, and by playing the shot in an area similar to my natural line I increase my % of makes.
5) Last but not least, no matter where I bowl....It is always the same, which is huge in the tournys.
With all that being said I would say go out practice throwing at just corner pins. You don't want to lose confidence or have self-doubt next you need one to win your match. Everytime I miss one (7 or 10) I make myself throw one game of nothing but...Also you can play the low-game. In case you aren't familiar bowl a whole game trying to get as few pins as possible with a gutter shot giving you a 10-count. Lowest score for each frame is 2. Cannot shoot at the same side of lane both times in any one frame. Lotsa fun! Good Luck