Here is a brown tie I made... I will get photos of just the onsie so you can see it better
What you need
1. scrap material
3. iron on
4. sewing machine.
1. You draw a tie on card stock and mine was pretty small because I put them on newborn onsies. I did mine in two pieces the knot and the tie piece. This is your pattern
2. Cut out the material in the tie shape.
3. Cut out the iron on in the tie shape.
4. Follow your iron on directions and iron the tie on the onsie make sure it is centered.
5. Then I used an applique stitch and sewed around the tie to ensure it would stay on.
That's it!! You have an adorable onesie. I paired my little man's onsie with leg warmers.