I really like the colors that are already there! :)

The dark green shutters and portico colors work very nicely to the wonderful woody surroundings.

The bright white front door color blends with the color of the storm door (which is an excellent way to make that area stand out AND appear more cohesive and therefore larger to the viewer's eye ....)

Perhaps consider building or adding window boxes to the two main windows to make them appear to be larger?

And also consider adding stair railings to the lower steps (paint them dark green or black to blend with the other ones on the top stairway) Safety is always a good selling factor! :)

For future consideration and selling your home -- you MIGHT expand/widen the front steps (if they are wood -- I can't tell from the photo) on each side.

Thanks Teacats! I'm surprised you like the color. A real estate agent called it "builder grade green". Agree with the window boxes idea but I think I'll have to have them made.

The stairs are all concrete so I think expanding them would be a major undertaking.

Though I love them, I wouldn't put in window boxes. You would have to drill into the brick. I like the green and can't think of another color that would be brighter but yet fitting for the woodsy look of the setting. Maybe you need to tweak the shade of green.

I assume you are aware the shutter on the right is off its hinge.

I agree with graywings. No window boxes. Also, it means more work for you to maintain the flowers in them.
I don't mind the green paint, but perhaps some others who are good at paint colors will chime in.
I would neaten up the landscaping. Although it has a nice natural look, to some it could appear unkempt and sloppy.

I'd tear off the portico and put something completely different there--- something charming and unconventional or unexpected, like an eyebrow shape or something round. The current porch/entry looks a little like an afterthought. It needn't be that expensive, and would completely change the look and feel.

For colors, I would do all white to brighten up the front--- white woodwork, white shutters, etc.

Some shutter/portico ideas to consider:

Medium gray like the roof or pick up a gray in the brick.

Sage green.

Griege but leaning more to the beige.

Burgundy/plum is very popular for shutters currently and I have seen that color against brick, but I'm not so fond of it against brick. It looks better against plain siding.

When I was deciding on shutter paint, I got some foam board and cut it to the size of the shutters, painted some colors on it, then taped it up and walked out to the street to see how they looked. You can get Color to Go samples at Sherwin Williams for about $7 a can. Might be worth a try.