Network delay can be influenced by several factors including propagation delay, transmission delay, queuing delay, and processing delay. Propagation delay is the time it takes for a signal to travel through the medium, transmission delay is the time required to push all the packet's bits into the wire, queuing delay is the time a packet spends waiting in a queue until it can be sent, and processing delay is the time routers take to process the packet's header and determine its path. Optimizing network configurations, choosing efficient routing methods, and utilizing faster hardware can help reduce network delays.