One very good example to this is your DNS connection. Your ISP doesn't care about latency. So they don't put up much infrastructure to handle DNS requests. Much of the time their servers are busy. Third party DNS servers are better at this. Or as suggested before, put up your own caching DNS server for your local network. That tweak will have a big impact on your network.
Afterall, whether they admit to it or not, ISPs are after profit. And putting up infrastructure for DNS is additional cost without any potential for gains.
Other than DNS, the other parts you can improve on are virtually unknown. But you can test your very own network to see what aspects can be enhanced. Sounds geeky. But it is very easy. Just so you have an idea, here is a website that has a network profiler and analyzer you can try out on your home network -- netalyzr.icsi.berkeley.edu.
Here is a screenshot of the profile of a tested network.
From there you can see that there is an issue on the non-randomized DNS ports. Minor issues include low bandwidth, which the owner has no control over. Internet connection in the Philippines is horrible, not to mention expensive. Your system's clock is also analyzed and is an issue which can be easily ignored.
So go ahead. Capture a profile of your own home network and see the analysis of the netalyzer. Chances are, there could be things you can tweak on your end of the chain. It helps to know.
