While I would advise just simply sticking to the speed limits put in place for yours and others safety, there are a a couple of tricks I've picked up which work at least in the UK!
Speed cameras have tolerances that are in place in order to stop people getting tickets when in fact they're travelling below the speed limit. After all it costs a fair bit for the authorities to distribute tickets and costs them even more if it gets disputed and thrown out, so it's in their interest to have accurate speed cameras!
The tolerance that I have learned to go by is about 10% over the actual speed limit as I've heard that this is the possible error that a speed camera could present when measuring speed.
A second point of interest is that car speedometers aren't actually all that accurate either, displaying slightly higher than you are actually going (this figure I was once told was +2mph) and if you've ever traveled with a sat nav in the car which shows speed, you'll have seen that the cars displayed speed is a fair bit higher than the reading on the sat nav. I have subsequently found out that the sat nav reading is actually the more accurate of the two (which I refused to believe for a long time) so if you're using one of those you can always ignore your own speedo and go with what that is saying.
Even with all these measures I still change my speed depending on the road conditions and situations that I am in. If it's an empty motorway then I'll happily go 90-100mph unless there are speed cameras around at which point I will slow down to just over the speed limit (+5-10 mph) and I'll usually slow down a bit when passing other vehicles (just in case of unmarked police cars) as if you're caught going over 100mph (or twice the speed limit) you'll instantly lose your license and will be taken to court so I save those speeds for solo drives on lonely roads.
After all that I would still just simply advise staying to whatever you're comfortable with, if you're going to break speed limits you've got to be prepared to risk getting a speeding ticket and to be honest sometimes people can just be outright idiots and deserve lose their license.
Anyways, that's the work around a I use and have never got a ticket or anything but as I said, I live in the UK and I'm unaware of it is applicable internationally but it might be of use to you.