Garlic Bread is an easy thing to buy but also an easy thing to do. We don't have to be stuck within one rule fits all. This is a tip. You can experiment, try and taste.

First of all, the Bread doesn't have to be officialy the Baguette. It can be a Sourdough Bread, a Pain de Campagne, a Ciabatta, a flat Bread... The thickness of the slice depends upon your own taste but I found that for better consistancy one centimetre to two do the trick while I would say that going for three centimetres is going very much on the very rustic side. However if you have a very good Bread within your hands, why not?

Second, as an individual coming from Normandy, that the Butter is essential. If you are lactose intolerant there are plenty of option out there to replace Butter. For myself, Isigny sur mer  salted Butter is my own choice. The Butter needs to melt inside the slice of Bread to make it luscious. It doesn't have to be overly greasy. It just needs a good spread upon the slice (2.5 to 5 mm)

Third, the Garlic of course is a crucial part. Rubbing the Bread slice with Garlic help to enhance the flavour, prior to put the Butter. Then chop the Garlic, place it on top of the spread Butter, evenly. 

Chop some Herbs of your choice, Chives, Dill, Rosemary, Parsley to make your Garlic Bread special before putting it under the Grill. It will impart another aroma to balance the one of the Garlic.