All good pointers: ACV, early morning breeding, lights if possible. A nice sunny morning never hurts either.
I'd also add some dark leafy greens (parsley, carrot tops, dandelions) to her diet and a couple of teaspoons of raw wheat germ (or 5-6 drops of wheat germ oil) over her food. Vitamin A and Vitamin E are important for breeding and they can both be lost from feed during storage over time or from heat.