There's never a mystery to slowness. If you record one of your plays I guarantee that you'll see some combination of infinity abuse, lack of manual locking, and inefficient placement techniques. Speed won't come overnight, but you should make steady progress as long as you keep playing. For now, try to avoid really slow placements unless they offer a strong strategic advantage. All you pieces should be placed at approximately the same rate. If this is already the case then you're either crazy inefficient with every placement, or you aren't manually locking. I wouldn't worry about it too much for now though. Survival is a more important goal when you're starting out. Take the time to learn the game and enjoy yourself.