There's not a lot you can do about startup times, but shutdown is, to an extent, governed by settings in the Windows Registry. Tweaking these can accelerate shutdown a bit. To do this, click on the Start button and type in 'regedit' in the Run box. Look for the following key:
In the right pane, right-click on the 'WaitToKillServiceTimeout' DWORD value and select 'Modify'. The default value you see may vary. On Windows 7, there was a value of 12,000 (in milliseconds). You should work your way down slowly, if you lower it too much you may experience stability problems with your computer. You can start by changing it to 10,000 then going down to 8,000 if everything goes alright.