Biscuits won't rise...?

Biscuit dough gets tough if you handle it too much; 30 seconds sounds like a long time of kneading before rolling it out. Your biscuit cutter must be sharp. Using a coffee cup or drinking gl seals the edges of the biscuit and prevents a good rise. And lastly - you can test out your baking powder by dropping a teaspoon of it into a cup of hot water. If it fizzes madly, then it's still good.