Using the system time has always been one way to create a more random seed; we were learning that back in the 80's. The trouble is that the sequence is still not truly random. This is "pseudo-random", since the outcome is still deterministic. It's possible to predict the outcome of your random number roll if you know the system time.
If you want a truly random number, you need to interact with something outside the computer. One way to do this is with the sound card's microphone. Even if you don't have a mic plugged in, it's still possible to get white noise through the mic preamp. You take a few samples from the microphone port and use those as part of your seed. Or have a person press a key on the keyboard when a symbol flashes on the screen. No matter how good they are, there will be a non-deterministic delay between the time the symbol appears and the time the key is fully depressed.
There are other ways of interfacing with the real world, as well: radio receivers, video cameras, even sensors that can detect radioactive decay. You could record mouse movement on the screen or use the location of a GPS device on he APRS network
The key is getting outside the processor and in to the real world. Once you leave the digital domain, randomness abounds.