This sounds like a *no-brainer* - but this is something that really does get over-looked... and it really becomes an *emotional* thing with some people.

Try to make it VERY clear what exactly your payment terms are.  You'll always get some that don't read them, or pay attention to them... but honestly, the majority of people WILL follow your terms.

Keep negativity OUT of your auctions!  The people that will follow them - will follow them either way.  The few that won't ~ won't no matter how NICE or how NEGATIVE your terms may be!  Don't make the mistake of *offending* your potential GOOD bidder (who WILL read it!), by trying to scare away the BAD one (who won't read it anyway!!).  I can't tell you how many times I've hit the *back* button, while shopping, because of a rude seller!

You'll also want CLEAR shipping terms, as well.  Let it be known how long it will take for you to ship.  If using Turbo Lister, it is VERY easy to put in different shipping methods.

*IF* you combine shipping... make your policy CLEAR and CONCISE!  You'll be surprised by the amount of multiple bids you'll receive when you sell similar items and give CLEAR Shipping Discounts in your auctions!