The best way to improve download speed is to connect the laptop directly to the router. A physical connection allows for better download / upload speeds; i.e. get an ethernet cable.
Wireless performance could be improved by newer drivers if any and if they specifically address a performance issue in previous driver versions. Otherwise, installing a new wireless card can help. Below is a link to the 3 best Intel wireless cards that supports 802.11ac. Your router must also support 802.11ac which has been the standard since 2014 I believe.