The Vibe
Serene and romantic? Boastful and brash? This one is the most fun to decide on. Make a Pinterest board, or a collage (digital or analog), using all your pieces of inspiration. Think of a few key words that will anchor the vibe of your wedding: fun, low key, memorable, unique, small, intimate, grand, unexpected, romantic, whatever rings your bells.
Overall inspiration
You can uses abstract pieces of inspiration or specific visual references, like flowers or colors you know you want to utilize. If there are photos from weddings you have come across that you like, save those too!
Use these visual storyboards as anchor point for your wedding planning.
Specific Inspiration
You can also create a board for a specific aspect of your wedding, like your florals or your invitations. This is especially helpful to bring to a vendor like a florist to give them an idea of what you're looking for.
Themes
This is also where you would pick a "theme". Personally, a theme has never really rang my bells. People don't live themed lives, why would we have a themed wedding? I like to think about color schemes and general vibe, and I like to pull in interests in ways that aren't totally on the nose. What I mean by this, is if your theme is "travel", you can make paper flowers out of maps, or you can install a cool installation like these that are both visually interesting and imply the theme without beating you over the head with it.
One last thing to consider is that a loose color palette and general vibe is much easier to execute and feels way more elegant and unique. All the elements can feel like they are in conversation with each other without necessarily matching perfectly.