Rate 1:
360 degrees in 2 minutes
180 degrees in 1 minute (60 seconds)
30 degrees in 10 seconds
To execute timed turns, use a nav instrument. Set your present heading at the top then work out which way to turn onto the heading you require (shortest route unless the instructor/examiner specifies otherwise). Segments of 30 degrees are easy to read from the compass rose on the nav instrument and each one takes 10 seconds. Quick bit of mental arithmetic, click the stopwatch and off you go - keeping an eye on the turn co-ordinator to make sure that you are maintaining a Rate 1 turn. Click the stopwatch and level wings. Let the compass settle and if you need to adjust, repeat the process until you're where you want to be. Might take two or three attempts. Some pilots turn and then start the watch - personal preference.
For small adjustments, (eg 20 degrees in 6 seconds) count the seconds in your head rather than use the stopwatch.