There's no specific point to change gear, but whatever makes the drive smoothest is generally the best way. I think changing up just 1000rpm before redline every time is a great way not to be smooth or sympathetic to the car... I hope that's only when driving quickly!
Not trying to be prejudiced here in any way, but Piotr have you noticed generally there are far more Americans who are inexperienced at driving manual gearbox cars and ask questions about how to drive them.. I guess as they're more common in Europe everybody learns them when they learn to drive, so it becomes completely natural
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black