Well there are different schools of thought on putting, including straight back and through vs. inside takeaway and release, and numerous training aids such as the putting arc but in your case I'd just start by putting between two rows of tees or two yardsticks laid out in a railroad track fashion...nothing over 4 to 6 ft. When you putt these short ones be sure to aim at a specific blade of grass, not just the cup, only take the club back far enough to get the ball 18 inches past the hole and accelerate.

Shade