Updated New Trader Tips from experienced BeerAdvocate traders (old version).

BeerAdvocate forum links with trading tips (requires account activation, sorry about that but I copied the best tip below)
Beer Trading Basics
Best Packaging Tips
New to this how the hell do you ship beer?
Question: Best way to ship beer?
Shipping preferences?
Shipping growlers
Growler question
International Shipping
Best way to ship beer

(The following is quoted from the last BA forum link above and was written by BA user RedwoodGeorge)
Packing advice

Think about the physics of the situation - what can break a beer bottle? If you do everything reasonable to protect against situations that can break a bottle, you're most of the way there.

Two major threats:

1) Something outside the box. What if the box gets dropped, kicked, pierced or crushed? Where's your bottle going to be? You've got to have durable protection between your bottle and whatever the outside world (aka 'UPS') can throw at it. If there's nothing between your precious bottle and the cardboard, your bottle isn't protected. A layer of peanuts is good but make sure the bottle can't 'swim' through the peanuts to the cardboard wall. Rigid foam, cushion foam or heavy bubblewrap are all good solutions that the bottle can't swim through.

2) Something inside the box. Would you put a beer bottle in a box full of hammers? Of course not. And yet you'd but a beer bottle in a box full of other beer bottles! Try smashing two bottles together and tell me one of them won't lose that contest. You've got to protect the bottles from crashing into each other. The first approach: more padding, this time on an individual basis. Most folk wrap each bottle in a layer or two of bubblewrap. If one bottle runs into another at least there's two layers of bubblewrap to absorb the energy. Better still, immobilize the suckers so they can't crash into each other. Three strategies:

a) pack the box -tight- with peanuts in between the bottles so the bottles can't 'swim' and hit each other. Remember the box will spend a week in the back of a truck so there will be lots of jostling during that time...

b) put the bottles into individual cells, much like in a case of beer. If they can't leave their confinement they can't come in contact with other bottles. Make sure the walls of the cells are adequately strong to restrain the bottles if the box is dropped.

c) bind the bottles together. This may seem counterintuitive but physics doesn't lie. Take the bubblewrapped bottles and tightly tape 'em together. That way they all move as a group instead of moving in different directions (sometimes towards each other)

Now that you've got the inside of the box well protected, make sure the box is well sealed. Don't use cheap tape. Expect the driver to leave it in a puddle of water in the back of the truck (because some will) The cardboard may have little integrity by the time the box gets to its destination so make sure the packing tape is there to help. For the truly paranoid, strapping tape (with the embedded fibers) is insanely strong. One complete loop of that will hold practically -any- box together.

How about used cardboard boxes? I generally avoid them. With all the time, money and effort being spent on shipping the beer, saving two bucks and using an old, soft box doesn't make sense. If it's in good shape then fine but don't cheap out at the wrong time...

Lastly, what if the cap should fail while in transit? Sadly it's not unheard of, especially if the beer is highly carbonated or if it's a twist off cap (with less grip than a standard pry-off cap). Some folk wrap each bottle individually in a ziploc bag, some line the entire box with a hefty bag. Either way if a bottle leaks the beer will stay inside the box rather than soaking through both and a) tipping off the driver that you're shipping a prohibited substance and b) weakening the cardboard of the box. It's not a bad idea to put some newspaper or paper towel in the box to soak up any liquid - it's much easier to contain a wet paper towel than many ounces of escaped beer.

Expect them (aka 'UPS') to drop your box. If you're not comfortable dropping your box (repeatedly) from chest height onto a concrete floor then you haven't packed well enough. If you hear -any- rattle when you shake that box like a five year old trying to get the last nickel out of a piggy bank, you haven't packed well enough.

Just keep thinking "plan for the worst" and remember that they (aka 'UPS') don't care about your package nearly as much as you do - pack with that understanding and your beer will arrive safe and sound.


Ratebeer's Guide to Trading
The Hop Press - Ship at Your Own Risk: Mailing Beer
Beeriety's 5 Tips For The New Beer Trader -thanks karmaiji27

If anyone has any good links or tips, post them here.

revision by statball— view source