On the final yarn over of the stitch, use the second colour

Drawing the hook backwards pull yarn through

Carry on stitches as normal using the new colour.  Every
3-4 stitches, twist old and new colours around to “carry old colour along. 

This ensures that the “floats” of the old colour are not too long and don’t get pulled too tight, warping the lay of the work

On the final stitch using the new colour, use the old colour for the yarn over

Drawing the hook backwards pull yarn through

The colour change is completed

How stitches look on the right side of work

How stitches look on the wrong side of the work with yarn carried across