2 Fall Couples

The first is my little sister and her Hubby:

I think they are a little cool I have to fix.

The before last one looks a little crooked, I like them on the pictures, they look at ease and in love (which is the point ). As for editing I'd give their face a little more color, they look pretty saturated atm.
The first 3 in the woods seem like they were overexposed? You could try fiddling with your curves for those but its ok.
GJ though

I love the second set, the exposures and DOF are great! With the looking back photos though I'd maybe have them walking and not just standing, maybe even looking at each other and not the camera.

x2 for svet's comment - especially with engagement shoots, the goal is to show a couple in love, not a couple at a photoshoot. The less they look at you the better imho.

I like the second set better.

For the first set I would have shot with a wider aperture, this shortens your DOF and isolates the couple better (similar to what you have in #1 of the second set), and it would take away some of the busyness of the not so interesting background.

You have some good ideas, and a good start, they just need a little tweaking.