Are there any standard techniques for controlling the speed of a servo?
Not built into the servo library. Using simple time delays as you describe will work if you are using just one servo and there is nothing else in the main sketch that needs servicing faster then the use of the blocking delay() statements. If you use millis() for tracking elapsed time you can avoid the blocking action of delay() and control the speed of many servos as well as assuring your main loop cycle time is fast enough to handle all else you are doing. See the blink without delay sketch example for how that method can be applied.
There has been a poster (or two?) that said they are working on modifying the servo library (or writing a new one) to use a optional velocity value for the servo.write() command. That would be very useful.
Lefty