I'm no expert on computer security but from what I read, there
are a few ways you can frustrate hackers from entering your
network, not prevent mind you, merely frustrate.
Firstly, don't broadcast your SSID. If your network is invisible,
people would need more effort to find your network. Use the latest
encryption that is available on your router. Even an old WEP is
better than nothing.
Don't forward your ports unless absolutely necessary. Don't use
DHCP. Use static IP addressing instead. If others can't guess your
IP, they can't log into your network. Separate your wired and
wireless networks. Linksys has this feature. Your wireless is less
secure than your wired network and thus it is a good idea to
separate them. Also, only allow your wired computer to access your
router. This prevents hackers from accessing your router
wirelessly.
Use strong passwords that is not subceptible to dictionary attacks.
Estimate the maximum number of computers that will access the
internet at any 1 time. Set the max connections to the router as
such. ie. If you have 5 computers, but only 3 would be connected at
any 1 time, then the router should only allow maximum of 3
computers to connect to the internet.
Also, some routers can set timings for the internet to be switched
off. If you know that between say... 4am to 8 am everyday, no one
would be using the internet, then keep set your router to
disconnect from the internet at those times regardless of if its in
use or not.
Of course all these does not guarantee that you'll be secured,
you'll just be better protected.
If I made any mistakes or missed out anything, feel free to point
it out. Thanks.