You can try the following...
Reduce the duration or intensity of the lighting, or use a timer to regulate the light cycle. You can also use shades, curtains, or covers to block any unwanted light sources. You can also choose the appropriate spectrum of light for your aquarium, such as blue or red, which are less favorable for algae growth than white or green.
You can reduce the amount and frequency of feeding, and remove any uneaten food or waste from the tank. You can also increase the water changes, and use a gravel vacuum to siphon out any debris or algae from the substrate. You can also use a filter media that can remove or reduce the nitrogenous compounds or phosphates from the water, such as activated carbon, zeolite, or phosphate remover.
You can introduce more live plants or artificial plants to your aquarium, which can compete with the algae for the nutrients and light. You can also add some algae-eating snails, shrimps, or fish, that can help keep the algae under control.
