I've checked prices up to 4 times a day and have seen different prices every time I look.
Seems to be much quieter this week.
No strategy other than to keep looking. At times I peek at how many seats remain to tell how full the flight I want already is, chances are if most of the seats are gone, the price isn't dropping more. If the plane has next to nothing reserved, the price is likely to drop.
Also check all airports in the area. For us, Delta is at Lexington, Louisville, and Cincinnati. Cincinnati flights are the cheapest 95% of the time. On the flip side, SW is cheaper from Louisville, even with SW coming to Cincinnati next month.