I average 6 to 7 minutes. It's all about look-ahead, which only gets better with practice.
Centers is a matter of making columns and putting them where desired. Check here
. If this takes more than 3:30 to 4:00 minutes to do this you need to work on look-ahead here.
Edges can be optimized beyond what some guides teach you. The most preferred to speedcubers is discussed in this
video. There are certain tricks you can teach yourself on how to get faster at this step, but once you have it down, it's only look-ahead you can really do to improve. This step tends to take the longest for many solvers (but not all). I finish mine in 3 minutes.
3x3x3 is the last step, obviously, but your choice in 3x3x3 solution has a good impact on your time as well. Consider learning different algorithms to compensate for the shape and size of the cube. Mine take usually 30 to 45 seconds. One way to improve your time by 5 to even 10 seconds on this step is to practice solving the 3x3x3 step on the big cube, not the normal 3x3x3 cube, and without inspection time.
Andreas Nortmann wrote:
Things like this are illegal.
If not I will pass an appropriate law.