Oh, I can help you! For a very reasonable fee
What's your style?
Subscribe to the home decor mag that's closest to your vibe.
Peruse for months, or read back copies quickly at the library. You don't want the latest trend, you want a sense of how to harmonize new colors and new textures with your old stuff.
While my house was being renovated top to bottom, I spent a year thinking about paint colors, wallpapers, furniture, etc.
I realized I kept coming back to colors I loved - not the trendy ones like grey. Best advice: pick what you love, not what you think is fashionable. I bought a color deck from Benjamin Moore to inspire me.
Think about how rooms will flow one into the other, especially if it's an open floor plan. Colors need to harmonize from room to room. You can pick two vibrant contrasting shades as accents (as in cushions on a sofa) against a more neutral background (wall). Look online for color wheels where they explain color combinations.
Usually moldings are shiny white against darker walls and ceilings (I love painting ceilings the same shade or a shade lighter than the walls - it brings the room together). But if you want a less conservative look, you can do the opposite! Light walls and darker shiny moldings!
Balance. If you're going to be very cluttered, the walls have to be calming. If you have minimalist furniture, you can add a scenic wallpaper as focal point on a long wall. British (or high-end French) wallpapers are beautiful and better quality than American.
Lighting is very important and sets the mood. You can get easily lost in all the options online.