No major tricks, upgrade your connection if you want more speed.
i heard you can alter the MTU Size in your router that will effect things little bit but the default "1480" work perfect. i tried to alter MTU manually using pings but didn't worked for me, so i am happy with the default.
Plus you can turn of wifi and use less devices while downloading large files. btw what in the world is "AB Network Services" look like a private cable net to me, in which case the bandwidth will probably be shared among many users, so in peak times it is normal it to be slow.
Better Change your internet connection.