A couple of tips for crocheting 2colour patterns.
When changing from colour1 to colour2, make sure to do the
change on the last stitch of the first colour.
At the top of the work you see the smooth colour change.
Always keep the thread not in use very close to the work,
and crochet around it to keep it inside the work.
This way, there will be no loose threads on any side of the work.