I travel a lot and so I try and think of a theme. Invariable my theme is nautical, because I am drawn to bretons! That way everything goes together.
So as a winter, you need to choose maybe two colours that suit you and that you have a lot of in your wardrobe, plus neutrals (black, white, grey, navy, again whatever you have). Then everything should go.
I do something like:
black denim shorts, black bistro crops, black tube skirt, dk grey merino jumper, plain white t shirts. (neutrals)
long sleeve heavy breton, anchor print dress, short sleeve breton, plain navy and white t shirts, loose cotton embroidered tops, navy and white stripey shorts (theme!)
Then the colour pop - red trousers (I know but I love them!), a red cotton silk scarf (useful for the plane and beach too!), red gel nails, red lipstick, maybe a red t shirt.
I find accessories hardest but wayfarer sunglasses go with everything, navy posh sandals and black birkenstocks and I travel in converse. I don't take heels but you could take a pair of wedges if you are going to do anything more formal. Those longchamp bags are great as beach bags, hand luggage bags etc. I usually travel with a small handbag outbound so I can allow for shopping and use the longchamp one on the way back!
I learned this from my mother who is a very glamourous traveller - her summer trips are bright orange, purple, cream and navy, her winter trips are khaki and navy with red and orange!