Knitting colourwork techniques
Use stranded knitting for small repeated motifs, intarsia for large separate blocks and slipped stitches for mosaic designs.
Work the technique
Stranded: carry the unused colour loosely behind. Intarsia: use a separate supply for each block and interlock strands at boundaries. Mosaic: work one colour per pair of rows and slip the marked stitches from the prior colour.
Try it on a sample
Try a 20-stitch rectangle with a 6-stitch centre block using intarsia, then a tube of 2-stitch colour stripes using stranded knitting.
Check and recover
A technique choice changes the reverse face, stretch and yarn consumption. Test the same method that the garment uses before measuring gauge.