When I was younger I learned that spares are very important. I was taught to always shoot at a spare using the key pin.Most of the successful tour champions go straight. WRW jr,Duke,Voss, Bohn etc... Double and triple wood spares the key pin in the farthest forward. Using angle for right side spares you would stand on the left side of the lane and vise versa for 7 pin side spares.If you nail the ten pin straight on then for any spare towards you you move your eyes left one board from your ten pin target used for the ten pin. You have 13 boards to cover a single pin so you don't have to be perfect just make the shot. Shooting a 7 pin right on you would move your eyes to the right one board for each pin in. So lets say, and I will use my favorite target and stance positions for this example, I shoot a tenpin standing on board 34 and target board 19 and make it right on. If I were to leave a 6 pin my feet stay the same and my eyes would go to board 20. If I leave a 9 pin since its on the back row the 3 pin is in front of it but 2ft in front I would imagine I left a 1 and 3 and move my eyes to board 22.If I leave a 3-6-9 the key pin is the 6 but I move my eyes 2 left to board 21 as you want to cover the 3 pin.
For the left side if I hit the 7 pin right on and standing on board 11 looking at board 19 I then move my eyes go to 18 for a 4 pin and 17 for a 2 pin. A 2-4-5 bucket is the same as a 2 pin as is the 1-2-4-10 washout....this system basically works on all lane patterns using straight lines. If the lanes are really hooking the initial target can be moved to the right 2 boards for 10 pin side spares and also to the right for seven pin spares by 2 boards as the main target .If the lanes are wet/tight then the initial target moves left from the initial target to accommodate the oil( reducing hook). Good luck and always shoot spares with angle but straight at them with no hook!