Never made Blueberry Gin but I imagine you'd make like you do Sloe Gin. Get a pound of sloes (or blueberries) wash then and throw any away that look a bit dodgy. Pierce the skins,and place in a large sealable jar, a 1ltr kilner jar is ideal, add sugar,I use a quarter of a pound to every then pour a bottle of gin in.seal the jar and give it a good shake do this for 4-5 days till all the sugar disolves then put it in a cupboard and leave for 3-6 months giving it a shake every now and then. When you bottle it filter though a muslin cloth and away you go. Thats just the basic recipe as everybody has there own little addition to the mix, I for instance always add a tea spoon of almond essence. As to the taste I wouldn't drink normal gin if it was the only stuff behind the bar but after 3-6 months with the sloes it's a completly different matter