You can donate milk and sugar to temples or the poor.
As Ketu affects your health, wearing grey-colored clothes will help minimize its malefic effect.
You can feed a dog daily with chapatis or rice.
Donate blankets and warm clothes to the poor.
You can use herbs like sage and bayberry to reduce the malefic effect of Ketu.
On every Saturday, light a Diya or lamp of ghee under the Peepal tree.