Dont know if it's the best method, but the method that dh and I have become rather successful at using is:
a) book the 1st segment on day 1 of availability ie: if it's a straighfoward return...we will book on the 1st day that the flight comes into the sytem plus 1 day with that 1 day being used for a phantom return
b) if it is a multi segment flight ie yyz-las-ppt-rar-las-yyz...we follow the above but depending on how many 24 hour stops and/or allowed stops we use we book 1st flight+ number of days needed to book ea segment...so if we have 4 then our 1st booking would be 1st flight in sytem +4 days so that I can book phantom segmen for ea of the 4...of course if its a routing that doesnt fly ea day you have to allow for that
c)we pay alot of change fees
d)we almost always get what we want (or pretty darn close)in biz class 2-3 times a year...I almost always allow for a little flexibility...if we are taking a land based vacation I give us a 2 week spread on either end....if we're doing a cruise etc. I become far more determined and as my dh says"anal"..lol
e)be prepared to spend alot of time on the AP web site looking for the flights you want...you cannot count on the usual # of day rules with some airlines..when booking a south pacific itinerary a couple of years ago I found that the NZ flights were coming into the system at completely different times than what was expected...in some cases sooner, in some later
f)cardinal rule....all this applies only if you are booking when the flights first come into the system
g) I spend far too much time on this
h) I cant wait till the "anytime" awards come in even if its just for AC and even if the points are far higher
i) but then Im going to need a new hobby

Andrew...happy to here about the AC changes...and Im sure the res. agents are extremely grateful too....do you know when(or if?) the web site will allow for this though....Im thinking about the YYZ-Hawaii routing that we've done so frequently...for this upcoming Feb. I decided rather than chance it I just called in at 7:00am for the outbound and booked the 1 ways, and did the same for the return.....it would I expect take some pressure off the phone lines if the open return could be done on line no?