The easiest way to explain it is that you want the parents to cover as many desired IVs as possible. Ideally you'd have all 5 covered from the get go, but not everyone is lucky that way. Doubling up on IVs before covering all 5 is also discouraged because while you're guaranteeing that doubled up stat gets passed if chosen, you're wasting time not covering that stat.
When you breed, you first want the right nature. Breeding the nature last will usually undo your work, or make it 25x harder as you grind through all of the options. When you have a parent with the right nature, ever stone them so that it's guaranteed to be passed.
At this point when you have a parent with the right nature (and possibly good IVs) and a parent with good IVs, grind until you get a baby that can replace one of them. If your froakie daddy has hp and speed and the son has hp, def, and speed, the father is redundant and replaceable. However, if hidden abilities are in the mix, only replace the mother (or father in ditto breeding) with another HA parent of the same gender or you'll lose the chance to pass on the ability.
At this point, all you do is grind out eggs with the following criteria:
1. Does the hatched pokemon have the IV spread (and possibly ability, gender, etc) that you want? If so, you're done. If not, move to 2.
2. Would the hatched pokemon make a better parent (better IVs, hidden ability, etc.) than you are currently using? If yes, replace it (be sure to move the daycare items!). If not, box it.
Only other thing to worry about is not to damage the 5 IV spread in the daycare with switches. For instance, if the dad has 3 IVs and is the sole bringer of perfect speed IVs, you don't want to replace it with a 4 IV son that doesn't have speed and is basically a clone of the mom.
You should eventually get 4 IV parents that have 3 repeating IVs and 1 unique to cover all 5, and then just grind for all 5 to be picked up.
