So, I've cracked open the first bottle of my first ever extract brew. I couldn't be more pleased with the taste: it's genuinely up there with the Beavertown smoked porter I was aiming for, with added freshness from the Columbus and Cascade hops, mimicking what the Kernel used to use in Export India Porter. But, while it has carbonated, there is no head to speak of. I did use flaked barley among the grains, added priming sugar and put it in the warm for a week followed by two weeks in a cool place. Any idea what I may have got wrong or could do differently?