If you are looking to improve your home interior design but also get some return on the financial outlay then one idea is installing plantation shutters.
These are fitted on the interior of windows and provide several features.
They usually come fully flexible in that they get let in the light during the day but will effectively block it out at night time.
In a bathroom they are perfect to maintain a level of privacy.
For houses overlooked by neighbors or passing pedestrians these window blinds would work very well. They are also very attractive and add an air of serenity to any space.
Cost wise it is probably prohibitive to have plantation blinds in every room so consider where you would need them the most.
The slats are usually between two to five inches wide and can be altered throughout the day, depending on the conditions or time of year.
Plastic are cheaper than wood and also easier to maintain, with a wide clean with a damp cloth. You can even get wood effect plastic which gives you the best of both worlds.
There are many companies where you can order from and they will install them as well. If you have awkward shape window or unusually big or small ones this could be your only route. Alternatively you can buy them at home stores ready to put up yourself.
If you are a keen carpenter then making them yourself would not be out of the question as it only requires quite basic skills.