Windows must be retained to be plain yet versatile since this is the most used portion of the house, you can be able to customize it the way you want it to be but it has to be sturdy and investment wise. To be able to set the image of your own window on how you would like it to be you can be able to paint their window frames with neutral colors, this can also ensure that your own window will not have a negative effect.
Try adding one or two color to your own frame pick a color that can be found on the opposite of the color wheel as it can be the best combination to add life to you window.
If you are not a fan of bright colors you can simply go for the more sophisticated yet subtle look, try the varying texture of your neutral colors combine the silk with sheer Georgette fabric in the window curtains even if you go for the neutral shade the texture can give a unique and lasting color.
If you have a room with two corner windows what you can do is to divide the strip corner wall space, use panels or even drapes that converge in that corner, the effect will be able to inter connect two separate window panes and give the image a large combination of one window.
Small windows do not appear to be as attractive as the large ones, a great way to make these small windows appear bigger and more dramatic is to be able to put light colored panels and start above the window and end past it, the panels must appear wider compared to the window adding decoration like the tie back, ring tops, and finials can help you enhance the image of the window you must however be extra careful to now over do things you must only choose a selected decoration to give it a punch.
Decorating your window depends on the image and the amount of money that you are willing to spend you can now focus on the primary design first and comes after will be the time and the money that you dedicate in order to achieve that kind of design and structure.
If you do not have yet the means to create the window that you perceive to have, you can start by just the control of the privacy and the light, install a very functional blinds and shades that will look good and can serve as the foundation for the decoration, later you may add the elegant panels, drapes and other architectural details like the finials and the tieback.