The idea of Scandinavian decor can be really fun, but the actuality of it can sometimes get overwhelming, with all of the color, pattern and design options out there. It can be hard tonavigate a style of decor that can become real busy real quick, and reign in all of the choices you have. The key here is to do it all within reason, and do it in a way that works for you.
Here are a few tips:
Go to the source.
Take a look at some of the Scandinavian design books and online resources that show how Scandinavian homes were historically decorated. Whether it be the Gustavian period, Arts and Crafts, or even edging into Scandinavian modern, take a look at how the style you like was originally used, and it will give you a sense of how it "should" look in its original context.
Like Dala Horses? Or painted furniture? Or red in general? Great. But don't use that exclusively. Learn to mix in a few of those items or colors with some good neutrals, some contrasting patterns, and just some generally calmer spaces for the eye to land. Which brings me to my next point:
Much of what Scandinavian decor is about is indeed light, bright and white. It is a common theme in Nordic decor, because for much of the year this part of the world is quite dark and pretty cold. It brings in what available light there is, and brightens up the space immeasurably. Additionally, it almost always stands the test of time. Light, neutral decor tends not to go out of style as often as most brighter colors and bolder patterns might. Then you can accent with brighter colors, and can much more easily change out if you get tired of it.
"Knickknacky" isn't a real word, but I bet you know what I mean. Carved wooden figurines and small items are fun and cute and can look great on a shelf or coffee table, but they can look really cluttered really fast if you are trying to cram too many things in. Pick a few favorites and put those out, and either get rid of the rest, or store them in the basement and change them out when you need some new scenery.
Make sure that overall, it is a look that YOU like.
You are the one who has to live in your home, and if you are putting together a look just because you think it is the way it is "supposed" to look, instead of what you love, you are going to get tired of it real fast. You'll also end of spending a lot of money on things you wish you had chosen differently, and probably be frustrated in a short amount of time. Think about what elements of design you are commonly drawn to, and see what catches your eye on Pinterest, in design books, magazines, and other people's homes, and then start building from those common themes that you like.
Remember: using a theme within reason will achieve much better results than overdoing it will. And also: work with the home you have! If it's just too much pattern/color/theme etc. save it for something else. Putting together a home should be realistic and attainable, not overwhelming and limiting.