i'm usually making garlic bread in a hurry as a side, so I try to keep it simple and quick. My only real secret is using Trader Joe's brand California Garlic Powder - which tastes much better than any other store bought varieties I've tried. I just melt some butter in a pan with the garlic powder and sea salt to taste. Then pour it onto a plate, and dip some Ciabatta bread in it to coat it evenly. Then I dust it with some Romano cheese and throw it in the oven to toast it. If the top hasn't browned enough by the time the bread is warm and toasty, I will pop it under the broiler as well for a moment. Then I finish it with some fresh parsley.
Another variation, is when I make a compound butter for steaks. I usually make a lot of this and use it up over time, but it also pulls double duty as a spread for garlic bread. A compound butter can be anything you like, just let some butter come to room temp, and add your favorite blend of finely minced fresh herbs along with some onions or shallots or green onions, and perhaps some fresh garlic. Mix it all together and season it to taste then spoon it out on to some waxed paper and form it into a log. Roll it up, and cover with some additional plastic wrap and leave it in the fridge for at least a few hours to firm up and for the flavors to meld. Normally I cut a piece off and put it on my steaks when they are right off the grill. But I will also smear it on some French bread and throw it under the broiler as a side.