When I start a design the first thing I do is think about what colours it should be and how those colours will work together to convey the feelings of the design. Only then do I think about the shapes and actual layout of a piece. I can't even see a composition properly until there's colour in it, everything just seems flat and the same.
Working in layers of card limits the amount of colours you can introduce to a piece, making it important that all the colours work together for the overall design. If a colour is there just for one tiny dot, then is it required for the design? Can that dot be the same colour as another layer? Does it then help bring depth to the piece?
I've learned a lot in the last year, about colours, composition, cutting and sticking. There's still a lot to learn. Maybe starting with colours isn't the most sensible working order but it's what works for me. Without them life is boring and everything becomes harder to distinguish. Maybe that's why I've always written with colourful pens, much to the annoyance of my teachers. My maths teacher probably had the hardest job, maths was orange.
Some useful colour resources:
http://www.colourlovers.com/ - make a palette for each of your projects, search through existing palettes, great for inspiration gathering.
http://www.informationisbeautiful.net/visualizations/colours-in-cultures/ - everything on Information is Beautiful is worth your time and attention. This is a wonderful diagram of what different colours mean within different cultures, notice how much it differs? It's always worth checking this out, specially if you're doing work for use in a culture you're not familiar with. Check out meanings for your own culture, it might surprise you.
