a bright fence, maybe a brightly coloured garden seat or brightly coloured giant pots for shrubs, a flowering tree or shrubs - try to get ones that flowers in the winter. Climbers like roses, bouganvillea or coloured jasmines if they grow in your area. If you don't want to put them on the side of the house, try adding a gazebo or archway to the left of the path.
While I love bright doors, mine is yellow and I love red and blue doors, I'm not sure it will look right on your cottage. You don't want to lower the value of the place and red is a hard colour to remove. I'm wondering if you reverse the door colour with the sidelights colour, so the door becomes the same colour as the reddish sills and the sidelights revert to the cream colour the door currently is. I think that will look better, but it may not brighten it up like you want. I think the main problem is the ugly landscaping - that is where I'd concentrate my efforts if it was mine.
I wouldn't put anything around the windows, bc it will take away from the beautiful stonework. I would paint the trim under the windows to match the new red door though, and maybe add color by planting flowers around the house.
Bi-fold shutters would stay inside the window openings, but may not give the visual appeal you're looking for. Maybe you can add some color and contrast with the window frames?
To accommodate uneven surfaces, you may want to consider using a grout pack between the shutter frame and the stone/rock surfaces. You may want to Google Five Star Grout to find the right product for your application. This technique can also be used for split face concrete masonry unit construction. Basically a stiff grout is pushed into the gaps with a small tool.
Add some flower boxes to the windows. Put red flowers in them to match your front door. Cute house, by the way.
Flower boxes are always an option. If you plant hanging baskets with flowers that droop down over the sides it will break up the boring stone work and add some vibrant colour. If planted right they can bring a house alive.
I've just purchased a French cottage that's in need of a slight face lift. I had originally planned on adding shutters to the windows, but the rock surfaces are so uneven that shutters aren't an option.
We're planning to change the stone pathway to a more central and direct path, and we're installing a new bright red door with full white sidelights, new lited windows, and larger porch lanterns. I'm just stumped as far as the shutters. What can I do to add a bit more color and break up the stone work?