You will need:

Vinegar
Lemon Juice (for cooking)
Water

Directions:

In the spray water add

• 1/3 Water
• 1/3 Lemon Juice
• 1/3 Vinegar
• Shake and spray around the house

You will need:

• 10 drops of Lemongrass essential oil
• A clean spray bottle
• 1/4 cup of hot water

Directions:

In a spray bottle add lemongrass essential oil, hot water and shake well. Spray along windowsills and doorways, directly on flies, or anywhere else you see fit. It leaves a nice refreshing scent as well.

Source

These cloves are considered as an effective remedy in repelling the house with flies. In this process, cloves come with a lemon combination which is another effective ingredient in which the flies want to resist the smell.

Ingredients:

• 25 - 50 Cloves
• 1 Lemon

Process:

• Take a lemon and cut it in halve.
• Then take the cloves and poke 6 - 12 cloves in each and every half piece of lemon.
• Make sure that you have to poke with the pointed part of the clove so that the bud always remains upwards.
• Place these cloves inserted lemon pieces on a plate.
• Now put this place on the table as it makes aromatic and beautiful looking, especially useful whenever you take meals with your friends at outdoors like picnics or barbecue party.

Flies will stay away from the scent of cayenne pepper. Mix a little in a spray bottle with water.

• Spray the cayenne mixture in doorways, window sills and other cracks and corners where flies might try to come in.

Flies do not like scents such as lavender, basil and mint. Place them near windows to keep flies out.

• The way the bags and water reflect light will resemble a spider's web, and flies always try to avoid those. 
• Fill clear bags halfway with water. Seal the bags and hang them near doors and windows.
• Hang old CDs and DVDs to achieve the same light effect.