Leave a tail long enough to work through several centimetres of fabric. On the wrong side, follow the route of nearby stitches rather than pulling the tail tightly across open space.
In a dense fabric, change direction once to reduce the chance of the end working loose. In a lacey fabric, avoid placing the end where it will show through an opening.
Wash the piece after finishing when the yarn care allows it. The fibres settle, and you can check that the finishing remains comfortable and invisible.
