Establishing "Drishti Ganesh" in the house means that you are bringing such a form of Ganesh ji in your house which protects from evil eye (drishti dosh), negative energy and bad luck.
Some important benefits of establishing Drishti Ganesh in the house can be:
1. Protection from evil eye – It is believed that Drishti Ganesh removes evil eye and keeps auspicious energy in the house.
2. Happiness, peace and prosperity – Ganesh ji is called Vighnaharta, hence his establishment brings happiness, prosperity and peace in the house.
 3. Success in every work – Ganesh ji is remembered before every auspicious work, that is why his appearance also indicates success.
4. Vastu defects removal – Many people believe that placing an idol or picture of Ganesh on the main door of the house reduces the Vastu defects.
5. Morale and positivity increases – His presence keeps the atmosphere of the house positive and the mind gets peace.
 Usually Drishti Ganesh is placed in the main entrance or drawing room of the house in such a way that it faces outside the house, so that it prevents evil eyes from entering the house.