If it were my room, I'd use greens so as to tie in with the garden outside. A green and cream floral for the mattress. Some mossy green velvet bolsters to fill the space around the mattress. Cream linen roman shades with 5cm green borders for the windows. A plaid wool throw for cuddles.

Here are lots of inspiration pics on Houzz. Save those you like to an ideabook on your homepage.

http://www.houzz.com.au/photos/query/window-seats/nqrwns

Pick a color or 2 or several, brighten up the space. Roman shades on windows in the color of your choice. Rug.. Replace picture with one with color. Side table for morning coffee, can be used for 1 or 2 people.

I feel like a few white and yellow throw pillows could add a bright feel, or maybe even some deep red ones if you want to add a deeper comfy feeling.

Green and navy

Mine is a window seat, not a day bed, but you get the idea!

A fluffy rug and a fluffy blanket. Some pillows. I wouldn't go overboard with colors there. You have a gorgeous setup that only needs a little bit more work.

I would duplicate the roman blinds you have on the adjoining windows and don't pull them as tight, so they soften the windows. You could add a wood stump as a table for your mug of coffee! (see last picture) placed under your art (size of art is fine) and a small fake fur rug on the floor. Creams, browns, soft blue or grey - keep it feeling natural and restful and let the view be the star with your décor complimenting. A long bolster pillow along the back section vs lots of pillows, so it has wider space for resting and concentrate the pillows at one end for your head rest and leave room for your feet - just place a lovely mohair throw on the end. I live in Canada and have similar weather and I would therefore make it cozy, warm and inviting. Adding handles to the drawers (see 2nd pic) may be a nice touch. Ikea may have some good choices and/or go to some small shops to find interesting textures and designs and add slowly when you find just the right item. You could also purchase fabrics and have a local seamstress cover the bench seat and pillows (some could have rope trim for example or a wooden button in the middle of a flap over).

Lovely ideas above. I'm going for preserving the simplicity. And I want you to keep that picture there. (I see a very pale blush background on it, hence my choice of cushion colour.) I couldn't find a suitable small chest to be your hall table, but I'd look for one in either black or white. Put some greenery on it.

https://www.houzz.com/products/missoni-home-federico-throw-blanket-black-and-white-prvw-vr~2255829

http://www.polyvore.com/10x20_pink_lumbar_pillow_cover/thing?id=61356519

http://www.ikea.com/us/en/catalog/products/50277393/

A pale blue and white ticking stripe on the mattress cover would tie in with the pillow you have, or you could make it a bigger pillow in a soft floral. Make the large art I mentioned earlier in soft shades to blue and green.

Here's a mockup of what I was thinking, though I would probably not mix a floral pillow with a floral mattress.

Tina, we've given you lots of ideas. Please tell us if you like any of them, or hate them all! It's hard for us to move ahead without hearing from you.

Thank you so much everyone! There´s a lot of creativity out there and I have listened to all of your advice.

This has really got me going and I feel inspired again. I have just started a new moodboard for the room and have come up with a couple of ideas out of your ideas. Would love to hear what you think:-)!

Down below I have just switched out the colour of the sheepskin into a grey one.

And here´s my second moodboard.

Another alternative for the windows in this one down below.

So now I´m all over the place. I think what I need to start with is to decide if I should use the tree stump or the 'antique' table under the wall lamp?

Would love to hear what you think.

Having them both like in the moodboards did not work in this little area.

Thank you!

I like the antique table better. Looks lighter, lifts the room. Your moodboards look great. The grey sheepskin feels more modern to me. Love the grey, white, black and pink colour scheme.

Love reading nooks. It's amazing how a little space is perfect for reading or knitting, daydreaming or scheming.

www.jossandmain.com is my favorite site for pillows. PILLOWS FROM JOSS & MAIN: I could look at these pillows forever. I think I might have an obsession. The way to navigate what they have, is to click on a pic and then scroll down to "more for you". There are hundreds. They have great quality and most are available with down/feather inserts.

www.allmodern.com has everything under the sun with a good selection of small tables and ottomans. Especially good when running a sale.

I would install a bookcase at the wall end at the right- the same depth as the cushion with the lower shelves for a wall hung light, and a bowl of fruit and the upper shelves for books. See pic below.

I happen to like simple curtains and not completely bare windows. It's not for privacy, it's to frame the view. Think of it as a frame for a special piece of art.

Move down the existing reading light.

Paint the base of the bench a color or dark brown so the focus is on the cushion and pillows.

Since everyone will kick off their shoes, add a rug.

Paint the area a soft color to enhance the pillows and cushion cover. This vignette should be a little set design.

Add a little side table and add an ottoman also.

I would have like to see a darker paint on the base.

I, too, prefer the antique table.

The antique table is better. But I think a demi-lune table might fit best. e.g.

While a demilune would be against the wall and therefore out of the way, the round antique table works very well as a small cocktail table, allowing you to move it to anywhere you want in front of the mattress so that you can place a cup of coffee or glass of wine on it.

That table would work fine if about same height as bed. I like it.

What a fantastic space to work with! I would go with a red and white or ivory geometric print to cover the base cushion. Darkening the base would be more expensive maybe but in the alternative also could help it pop. Maybe just a few bigger cushions, not too many. Good luck!

What is the height of the mattress and also of the demilune?

I loved the tree stump until I saw the delicate wood one. I adore it. Roman shades if you even need any window coverings. Less will be more. Just 2 or 3 more pillows I think.

Love the white/grey european linen pillow! Thanks for sharing.

I'll probably work arond the antique table.

I like the out doors colors brought in there.

If you will truly use this space rather than just a decorated view, then I suggest large, supportive rectangular pillows (probably two) at the end where the picture is. This can support your back for reading and enjoying your garden view. Less is more. I think an evergreen covering for the seating so you don't have to be concerned with any marring. Some creams and whites in one or two other smaller throw pillows - perhaps something botanical.
For the floor I would use either the faux fur rug or sisal. Select a pull up chair at the corner of the foot end. Use a garden stool for your coffee cup table or other moveable table as large as space allows.
The curtains you already have in place work perfectly to soften the view.