@Maggiesfarm
For goodness sake, I know nobody who doesn't know how to pack a parcel. Where have you been all these years? It's a very basic skill which I would have thought we all learn early.
But there's packing a parcel and there's doing it well, incorporating a few little tricks that will save you a lot of money and/or hassle.
Eg not inadvertedly going slightly above Royal Mail's parcel size limits or weight limits that can make it a lot more expensive. Sometimes it's just a case of squishing the parcel down a bit or trimming a bit off the packaging.
Knowing which of the parcel companies is cheapest for a particular weight of parcel. Knowing which services to use and those to not use. Which parcel companies charge extra for remote areas, and which don't?
Knowing when to use Royal Mail special delivery, which for higher value parcels, is by far the cheapest way to send it properly tracked and insured, provided you stick to the weight limit, as the price then sky rockets.
Knowing when it's not worth paying for insurance, because nearly all parcels do get there, so it's better to just hope for the best, and replace the odd lost parcel out of your own pocket, rather than pay for insurance on every parcel you send.
Knowing where to get cheap packaging, because if you do things like buy boxes in the Post Office, you might as well kiss goodbye to any profit you make selling low priced items.
Without a bit of knowledge from more experienced people, you can make a lot of expensive mistakes when you're inexperienced and not confident about the process.