Not Enough Light
If your African violet plant is not blooming, the most common cause is that the plant is not receiving enough sunlight. African violet houseplants thrive in bright, indirect sunlight. Bright indirect light can be found in places close to an east-facing window or a few feet back from an unobstructed southern or western window. If the southern or western window has something like a sheer curtain or natural shade from a tree or building outside, the plant can be placed a little closer. Avoid direct sunlight and keep the plant away from any open vents and drafty windows. Rotate the plant now and then to ensure all the leaves get equal sunlight.
Uneven Watering Routine
To keep your African violet blooming, you must keep the soil evenly moist, but never soggy. Water when the soil volume is 25% dry. This plant likes to be kept moist, but does not like to sit in soggy soil. Avoid getting the leaves wet, and the bottom-watering method is recommended. Place your plant in a sink filled with 2-4″ of water. Leave the plant to soak for up to 45 minutes. Test the top of the soil for moisture. If it still feels dry water a little from the top. When your plant’s soil is evenly damp, drain the sink/tub and allow the plant to rest while it drains thoroughly.
If your African violet is actively growing, it might need a fertilizer boost. Use a fertilizer formulated for African violets to encourage flowering.