Colour has always been my "thing" it comes naturally to me so I choose colour instinctively rather than thinking about it.
I love all colours, some better than others but each has its place.
My palette is worked around the rainbow and tertiary colour wheel pictured below, there are 12 colours in my wheel which are all the same tone and level of saturation, this means they blend together like paint to form a continuous rainbow.
I don't use black or white, as I like my colours to be clear and true, black dulls colours and white over saturates them.
I don't use variegated yarns unless the colour variations in the yarn are very similar in hue and tone.
I often find that variagated yarns look beautiful in the skein, but don't work as well when crocheted, I don't like the fact that I have no control of where the colours appear and which colour is next to which, plus crochet creates blobs of colour as opposed to knitting which creates stripes of colour, but which can result in the colours pooling.
Up until 2015 all my designs were made using The Natural Dye Studio's plant dyed colours, sadly NDS closed in April 2015, so the colours are now discontinued. the best way to make these older designs is to make them as scrap blankets.
Scrap blankets and yarn types
There are a lot of crochet blanket patterns that are written for one particular yarn.
This can end up being very expensive, especially if you are a yarn snob like myself.
So I am a firm believer in stash raiding and scrap blankets.
I normally use several different yarn types in the same project, as long as they are the same meterage they should work together.
The different textures and types don't really matter as they add an extra depth to a finished project, you will be really surprised at what works together.
Using scrap yarns from your stash also means your blanket will be really personal to you and have a story of its own to tell, you may end up with a blanket that has left over's from projects you have made for friends and family or a favourite project you have made with extra special yarn.
When I start to design a blanket I select colour collections from my existing stash and add to them from where ever I can find a suitable yarn in the right colour.
I find it helps to photograph the collections so I can see the colours from a different perspective, it helps me decide which ones to keep and which ones to discard.
I normally use 4 ply and so have a big 4 ply stash, but even still I never have enough :-)
When I need extra colours I always start by looking at my indie dyer friend's websites and then move on to look at brands such as Drops Alpaca, Cascade 220 fingering, Knitpicks Palette yarn and recently I have discovered King Cole Merino Blend 4 ply.
All these yarn's have a good selection of colours to choose from.
You can find lots more details on my Recommended Yarns page.
Crocheting with different yarns and colours
It is important to spread the different yarns and colours evenly throughout the blanket/project.
Otherwise you will end up with a very lopsided looking project.
This is easy to do for a design that starts in the centre and works outwards, simply start with one yarn and substitue it with the next yarn when it runs out.
But a design that starts on one side or in a corner is a little bit more difficult, you will need to alternate between the yarns for each round/motif to obtain an even spread of colour/texture.
So I recommend you raid your stash and start experimenting :-)