The KYSS principle is something I teach all of my students.
Keep Your Scent Simple
If you have a good perfume brief, and you know the oils you need to add, use those first. And then play with modifications and embellishments.
Use your oils with intention.
I was recently commissioned to design four fine fragrances for a luxury candle brand in the USA. The client has very specific ideas about what they want. They gave me their briefs, and I designed fragrances around them. Every single oil within my design was put there with intention. Each oil had a specific purpose and reason for being there, and that's what you need to figure out with your fragrance.
Imagine it like this. You're hosting a party and you ask each guest to bring something. What are they bringing to the party and why? What value will they add to the cuisine and ambience? If everybody brings sausage rolls, it’ll be a very dull buffet. Surely, you'll need some variety in there. Maybe there's even a theme.
Don't try to impress your customers by adding trendy ingredients or hundreds of oils for no reason other than you've seen other people do it. Be true to yourself. If you're using lots of natural ingredients, these are complex in their own right, so you can keep your scent simple and light.
"When we put too many ingredients into a formula, it tends to turn it into a millefleurs. That thought hit me. From that moment. I told myself, ‘I must work simply’. I clung to the motto, simplify, simplify, simplify. Only when they reach the peak of their talent do artists begin to simplify their work.” Edmund Roudnitska
Less is more. You can always add, you can never take away.