Widows on the north side of a building are ideal for views, because everything you are looking at from these windows is facing the sun, and presenting its best lit side to you. For the same reason, a northern window is getting tons of reflected light from the sky and the landscape (or the fence/wall/other building placed just a few feet away) and no direct sunlight at all. So in every way, it is just the opposite of the southern window.
Of course, this means that the problems are just the opposite too. Instead of too much light, you might have the issue of not enough. A good architect/designer/builder will ideally plan for larger northern windows, to take better advantage of the view and the daylight, but for all of the reasons listed previously (and more, suppose the lot to the north is an apartment building, then you have privacy issues and no view) sometimes this ideal plan goes awry.
As an example, the building that I live in now was clearly planned with absolutely no thought given to the cardinal directions. I know this, because the same basic building footprint is repeated about 7 times in the complex, and the orientation is different each time. So here is my "lovely" northern view:
10 feet of concrete, 10 feet of mulch, a mossy fence and an ugly building. No sky, no landscape. But even this one small door window provides ample light for our kitchen. This is a cabinet door opposite the window, and look how clear the shadow is:
Because the light is diffuse, if my hand moves away just a little the shadow disappears. With bright, glossy white cabinets opposite the north window, I never turn the kitchen lights on during the day. Which brings us to the point of this post: maximizing that light.
In terms of daylighting, the worst thing you can do with a northern window is put a lot of large furniture or appliances right next to it. This reduces the angle of light coming in through the window, and therefore the amount of light. If you must put something right by the window, it helps if it is a bright color. The idea is to allow an uninterrupted path for the light to come in through the window at any angle and make it to the far wall, the ceiling, or the two perpendicular walls.
From there, some of the same tricks in the southern window post apply. Namely, mirrors and bright colors. A large mirror opposite a north facing window bounces light back into the room, but also it has the added benefit of making the view accessible from almost anywhere. If you are seated with your back to the window, you can still see the view in the mirror. Mirrors also make the room appear larger, both through the psychological trick of the appearance of more space and because as light fills the room is seems to expand. When the ceiling and corners of a room are dark, it seems to close in on you.
I recommend against curtains or blinds on a north window unless they are necessary for privacy. Putting anything between the window and the room reduces daylighting and obscures the view. Of course, if your bedroom or bathroom is on the north, you may want to fully obscure the view in, but otherwise I say embrace the outside world and leave the view open.
In terms of colors, I would recommend that walls be bright. Blue and yellow have the highest reflective index but any color that is pale (i.e. closer to white) will do well. You can also use high gloss or semi gloss paints in a room that has only northern light, because there is little risk of glare when the light is so diffuse. Ceilings should also be very bright. If you are a renter and you think you have white walls, you may want to take a closer look: building owners love off white colors like Swiss Coffee because they appear white at a glance and don't get dirty as easily, but they are actually tan. This could be reducing the amount of bounced light in your rooms by a great deal, and going for a more true white can significantly improve lighting conditions.
Last note on color: if you want to have a darker accent color on one wall, make it the wall with the window. The window is already providing all the light you need in that direction, so the bounce from that wall is redundant.
When planning a building or home, it is ideal to put the most public spaces and the spaces that you want to have the best views on the north. If you are renting or buying an existing building, however, the designer may not have considered this, or decided something else was more important, in which case a private room might end up on the north. In this case there is not much that you can do to get the privacy you need without blocking at least some of that light. Possibly the best option is an adhesive film that scatters the light a little but lets most of it pass through, like the one in the add there, or at this site. A completely frosted glass or film, however, would reflect almost half of the light back out the window. This option is not very cheap, and the film can be difficult to cut and apply just right, but with a little patience and care it can solve all your privacy concerns without much light lost.
Also, because the film can be difficult to cut just right, consider leaving a one inch gap around the edges. This will not be enough width to see anything through the window, and it can make uneven edges much cleaner looking.
So aside from the privacy concern, the advice is pretty simple: just get out of the way and let the light do the work for you! Avoid obscuring or absorbing that light before it has bounced around a little, and you should have a beautifully lit room from dawn until dusk.