Asking for a friend who is trying for her first baby: what is the best way to measure ovulation?

I'd say the most convenient and hassle free way would be ovulation predictor kits (OPKs). OPKs are able to pinpoint your date of ovulation 12 to 24 hours in advance by looking at levels of luteinizing hormone, or LH, which is the last of the hormones to hit its peak before ovulation actually occurs. All you have to do is pee on a stick and wait for the indicator to tell you whether you're about to ovulate.