Securing your router is one of the first actions you should take. Taking the time to set up proper security will go a long way. The following checklist is an 8 step guideline compiled by router security expert Michael Horowitz.
There is actually more steps at his amazing web site Router Security.
Don't use a modem/router combo, keep them separate
Change the login and password used to access the router. Check your router manual for instructions
- Use WPA2 with AES for Wi-Fi encryption
- Wi-Fi password should be at 14 characters long
- Disable Plug N Play(UPnP) and/or NAT-PMP on Apple routers - see point 12
- Don't use the default network name, choose a custom SSID name
- Use a Guest Network
- Turn Off Wi-Fi Protected Setup (WPS)
- Turn off Remote Administration - see step 4
- Check if ports are open with online testers
- Update the Router Firmware - see point 15
Check out the in-depth checklist with much more details for a deeper understanding and then read the rest of the site. It's amazing!