Using a large skillet or pan over medium high heat, heat 1 tablespoon of olive oil. I usually use enough to lightly cover the bottom of the skillet. Place the bread slices down into the pan and let heat up. After a few minutes, you'll hear the bread starting to cook and toast, you can turn the heat down to medium.
After about 4 minutes, flip all the bread and toast the other side. Feel free to add a touch more olive oil if desired but it's not necessary. I usually only toast the other side of the bread for about 3 minutes. Remove the bread from the heat and immediately rub each slice with a garlic clove if desired.
*I love using French bread, or any baguette or round artisan bakery bread for this. Sliced sandwich bread isn't ideal but will also work.