1) Get the Zauber Perlen, those are sets of small balls that form a gradient.
Alternatively, get a Zauberball or cake and match individual colors in it. Say you want a striped sweater. Start with a Zauberball in multicolor. Then match some of its colors so you might have a blue ball, a green ball, and a yellow ball. Do a solid stripe of each and then a multicolor stripe. Same trick works with multicolor yarn from recycled sari silk.
2) The Vivienne Files is all color coordinating fashion presented in ways that are easy to learn and copy.
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Alternatively, get a Zauberball or cake and match individual colors in it. Say you want a striped sweater. Start with a Zauberball in multicolor. Then match some of its colors so you might have a blue ball, a green ball, and a yellow ball. Do a solid stripe of each and then a multicolor stripe. Same trick works with multicolor yarn from recycled sari silk.
2) The Vivienne Files is all color coordinating fashion presented in ways that are easy to learn and copy.
3) How to Simplify Fashion has some advice on color-matching.