I am no expert, bit have shipped some. It is really not difficult, but very expensive so it usually hard to make it worthwhile for you and the buyer unless it is either a lot or something that's a bit more unique that people can't necessarily find locally at a reasonable price.
You can save some money using third party shipping companies where you print a shipping level using their account with Fedex/UPS so get a discount rather than if u just doing low volume shipping with your account.
As far as packing dont underestimate how roughly the boxes are handled. Obviously we'll sealed appropriate bags/containers, but then fill in all empty space so stuff can't bounce around. A heat or cool pack is often needed depending on to/from location. This time of year is great because of more moderate Temps in most of country.