First pick off the dead leafs. Make sure the leaves are not touching the planter. Then move the violets in a bright window. Don't put in sun. Fertilize.
African Violets are very touchy. The "African Violet Food" that they sell in the garden store, is not a hoax. It really works. African Violets love it, and they usually refuse to bloom until you give them some.
Every time you water the african violets mix a good but mild fertilizer with the water. This will give
them a constant feeding of the nutrients they need to bloom.
A method to get them to bloom is the constant feed method. Use weak fertilizer with water to feed the plants every time. Peter's fertilizer is a good product.