WFQ uses a flow based analysis on the traffic stream. Flows are identified based on the layer 3 and /or layer 4 parameters.
The higher the precedence, the more bandwidth it is going to get. Please note that these queueing techniques come into place only during congestion.
PQ is a method of giving priority service to delay sensitive traffic, so that they are get out of the queue as soon as they come. this minimizes the contention between delay-sensitive and non-delay sensitive packets.