Before doing anything else you will need to make sure that you have some basic cooking knowledge and skills to perform this task.
Now consider whipping an egg until it is not stringy. Make sure you use a large sized egg for this purpose.
Now take a bowl and clean it thoroughly using soap and hot water. Add salt, pepper, garlic power, onion powder, cayenne pepper and beer into the bowl and mix it well until it the ingredients form a thick paste.
Now add flour into the mixture and continue to stir until the mixture becomes smooth. Wash and rinse any food item you intend to fry in your homemade beer batter. Even if you are trying to make onion rings, you should rinse them before frying to ensure there are no bacteria or germs on it. Moreover, the water on the food items will help the batter stay on.
Immerse the washed food item into the beer batter to thoroughly coat it before placing it in the frying pan.