Nothing here is especially fragile. What matters is that it arrives clean, complete and ready to use safely.
Clean and dry first
Wash what the label allows, dry it completely, and never pack anything even slightly damp — three days sealed in an Indian parcel and fabric arrives smelling of mould. Say in the listing what you washed and how.
List every part in the parcel
Straps, pins, fixings, tools, rain covers, inserts. A small fixing lost in packing material is a buyer who cannot safely assemble the thing they bought. Bag the small parts, label the bag, and write the count on a note inside.
Include the manual
Printed if you have it, or the manufacturer's link written on the note. For anything that must be installed correctly, the manual is part of the item rather than an extra.
Clothing and soft items
Sealed plastic bag against damp, then a mailer. Packing clothing covers the rest.
Prams, cots and large items
Fold and secure moving parts so nothing can swing. Wrap wheels separately so grease cannot reach fabric. Protect every projecting part. Check the size and weight with your courier before you quote, and offer collection where it makes more sense.
Hard plastic items
Car seat shells, high chairs, bath seats: bubble, boxed, voids filled. Cracked plastic on a safety item is not cosmetic damage, so pack as though it matters.
Questions people ask
Should I dismantle a cot?
Yes, with every fixing bagged and labelled, and say so in the listing.
What if I have lost the manual?
Write the make, model and year on the note and point at the manufacturer's site. Say in the listing that the printed manual is missing.
Do I need to sanitise?
Clean to a standard you would accept yourself, and say exactly what you did.