What helped me the most with timing the boil is a cheap digital timer on my kitchen stove. When I got the wort to a boil, and then add the first hops I set the timer for 60 minutes. When the timer hits '15', then it's time for the 15 minute hops addition, and when it hits '5', then it's time for the 5 minute hops (or whatever the schedule is). I still use a digital timer every time, instead of trying to remember what time I started!
