Many forgers try to make Staffordshire figurines that look older than they really are. They put fake dirt on these. It's sprayed over a piece like a brown film to look like old smoke. Sometimes they rub the dirt into the cracks and into the glaze. They even rub bits into the unglazed portion on the bottom of a piece.
Colors can also be a give-away.
These transfer-decorated roses are very suspicious as well. Still, detecting new from old can be difficult. The old ones were made by hundreds of different factories and they all had different ways of painting and molding their pieces, so there's no one rule for assessing them. You have to look at all the features to make a decision about a piece's authenticity. All other things being equal, larger pieces usually sell for more than smaller ones.