For a cottage I would do subway tile or bead board.

I'm sorry - but the above example resembles my bathroom floors too much:)

You can use white subway tile or a color. Same with beadboard - you can paint it any color you want. I know gray is in, but since I'm not fond of gray, I might consider a blue or green color.

The beadboard paint is Hirshfield's 748 Balance.

Cabinets: B.Moore White Dove [blends with other colors in the room]

Sunnyside Road Residence Kitchen · More Info

Wall color next to the cabinets: Benjamin Moore Pale Moon 289.

Sunnyside Road Residence Kitchen 4 · More Info

Pale Moon 289 Paint - Benjamin Moore pale moon Paint Color Details · More Info

Pamela, are you going to post photo of your kitchen? :)

The color of your backsplash will be partly affected by your countertop. Cottages are simple and a good way to go about the backsplash is to take one of the lighter colors of your countertop and do a subway tile. However, with the white cabinets you also have the opportunity to do a color - think more beach cottage with a blue or green. You could also do a taupe and even gray - I just find gray limiting as to wall color - then you usually have to go gray there too, and for me, that just gets a little too white and gray - but some people love that combo.

Beadboard is flexible because you can paint it any color you want. If you are on a very tight budget or just cannot make up your mind about beadboard, you could do the beadboard textured, paintable wallpaper - about $20 a roll at Lowe's. This would probably be a temporary solution - it would last at least 5 years or more. I used the beadboard walpaper in my powder room because I may change out the countertop and did not want to encase it in beadboard. I also used it in my basement kitchenette - in case I change out the style down the road.

Here it is in a Pinterest kitchen using the beadboard wallpaper:

My powder room:

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~45787943

The lighting is not great for showing the beadboard in my kitchenette, but here it is. A skirted sink base and small area of open shelving can be cottage. Also, consider vintage or botanical art and pewter or silver trays.

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~65270573

Here are some unasked for thoughts:) I am short and would not like the microwave over the range in my kitchen - I don't like reaching up for hot food and it crowds the cooking space. It is possible the whole microwave and cabinet could be moved elsewhere. It is absolutely fine where it is, but if you ever thought about moving it, now is the time to really think on it because it will effect how high you do your backsplash over the range. A stainless hood would look great there, and if in the budget - a wood hood with vent insert painted to match you cabinets really says "cottage".

Your cabinets look new, so this is probably not an option, but if they are older, you can replace the center panel with glass on some.

I put vintage china on my soffits. Since there are so many styles of plates available, plates on the soffit is a possibility. My kitchen has wood cabinets, but I've done it in a vintage / cottage style:

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~93784356

https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~93784291

My farm sink is the Kohler Whitehaven "short apron" style which can be installed on a standard sink base cabinet. It was a little pricy, but I love it - one of the best changes i made to my kitchen. The Kohler Vault is a stainless apron front that also comes in a "short apron" style. The Vault comes in both under and over mount styles and is less expensive. The Ikea Domsjo is an over mount fireclay apron front sink which may fit on a standard base - I'm not sure. There are some home bloggers who have used it and there might be some info on the Internet. It is very reasonable, but does have much more potential for chipping and crazing then the cast iron Whitehaven.

Don't forget a pretty window treatment: