Wait to battle and earn EVs until you get the nature and IVs you want.
You may want to level both up so it won't cost you so much money in Day Care.
This is how I do my breeding to avoid filling my boxes more than I already do:
1. Put parents in Day Care.
2. Save.
3. Collect 4 eggs.
4 Take one parent out of Day Care.
5. Hatch eggs (flame body or magma speeds this up as well as hatching power)
6. Check eggs if they look promising take them to the Judge.
Are any of them better than current parents?
Yes then
Put it in Day Care repeat above steps.
(I usually breed with a Ditto that never comes out of Day Care. You'll need to make sure that you always keep a male and female.)
No then
1. Hit power button which closes the game.
2. Re-open game.
3. Walk around until there is an Egg.
4. REFUSE egg (it's the same as the first egg you just checked.)
5. SAVE (important I sometimes forget to)
6. Collect 4 eggs repeat as at beginning Steps 4-5,
I find this helps with box space and saves the trouble of releasing lots of Pokemon