To propagate an African violet, the most common method is to take a healthy leaf cutting with about 1-1.5 inches of stem attached, then root it in a moist potting mix, typically a blend of perlite and peat moss, at a 45-degree angle, keeping the cutting in a humid environment with bright, indirect light until new plantlets develop at the base of the stem; you can also root the cutting in water first before transferring it to soil. 

Key steps:

Select a healthy leaf: Choose a mature, firm, healthy leaf from the middle of the plant. 

Cut the leaf: Using a sharp, clean knife, cut the leaf at a 45-degree angle, ensuring at least 1 inch of stem remains attached. 

Prepare the rooting medium: Use a well-draining potting mix with added perlite or vermiculite for better aeration. 

Plant the cutting: Insert the leaf stem into the potting mix at a 45-degree angle, making sure the stem is fully covered. 

Provide humidity: Cover the pot with a plastic bag or plastic wrap to create a humid environment. 

Light conditions: Place the pot in a bright, indirect light location. 

Watering: Keep the soil moist but not soggy. 

Monitor for roots: After a few weeks, check for root development. 

Separate plantlets: Once the plantlets are large enough, carefully separate them from the mother leaf and pot them individually.