This was born out of sheer laziness.
Often, when I'm trying to make something basic and quick (think: Egg Beaters for breakfast, simple broiled steak), I end up using four basic spices - salt, pepper, garlic powder and onion powder. Rather than having to open up a few different spice containers, I worked out a rough proportion, and I use this as a base seasoning for nearly everything. By no means is this the only thing I use, but it is a great quick starter, and many of the recipes I post here will involve this. I recommend making a batch, storing it in a sealed container and using regularly.
1/2 tbsp salt
1 tbsp pepper
1 tbsp garlic powder
1 tbsp onion powder
This will fit nicely into a 4 oz Glad container, and last a while. If you want to make it larger, just keep the 1:2:2:2 mix ratios.