Wow, great points, and thanks to all of you for all the info!
3.) Rotate stock! People will stop checking out your vendor if it always has the same stuff on it. If something sits on on the vendor for a few days, either remove it and hoard it for later sale or move it to a "reduced price" vendor.
Just a counterpoint to that - from a crafter-shop perspective: Do not rotate stock, but
commit to those items you are selling. If you have a fishing vendor for example - work to keep it stocked. Same with recalls, furniture, potion kegs etc. Why? Because you get returning customers who recall/gate to your shop because they know you carry this and that item.
I have been a shop keeper in UO since I started playing, but recently stopped because I found out I missed so much else of the game. At the most I had 27 vendors, mostly crafted goods - all stocked by me. Many times restocking vendors was all I had time to do with my playing time. I have never had a Luna vendor, I like the "shop" idea much better. Maybe some day when I figure out how to price armour and jewelry
Here is my list from a crafter-perspective. Note: You will not get as wealthy as those selling artifacts or high-end armour, but gold will still trickle in:
Always keep your vendors stocked. Always. You will lose customers fast if they recall in a few days apart and still find your vendors empty. And, commit to your stock. If you start selling orange petals - then stick to it.
Display, always important. Make it easy for customers to find what they want by name on vendors, display in front and display in the vendor bag.
Everything sells eventually, at the right price. Yes, even GM armour - that so many here on the board claims can`t be sold. Bullocks. There is still a market for crafted goods of any kind.
If you have a shop in the middle of nowhere you face something different than that of a Luna shop. You have to work at getting your shop known, you need to work getting a customer base. That means dropping runes and gating, you can`t avoid it. Decide how much time you want to spend on your shop and advertize according to how much traffic you want. This is rather important point, as you quickly can feel overwhelmed and find out it`s too much work to keep stocking. Or the other way - you don`t get enough traffic to make it worth your while.
Decide pricing: Resellers will always find you. Sometimes you want them to find you, other times you wish they would keep away. But you need to price your wares with the resellers in mind as well. If you price items that can be easily sold in Luna cheap - you will always wake up to empty bags. If you price your wares according to Luna prices, you will have a hard time selling anything.
And then there is the time thing. How long time and resources does it take you to gather what you sell? Do you want those items to move fast or do you want to be the last stop for someone that haven`t found anything else in those other shops they have tried? Deciding where to place your inventory is one of the most important decisions you have to make. Cause it`s not so easy as a Luna shop with a 50% markup when you sell wooden benches
Can you still earn gold by selling crafted goods? Yes! Don`t listen to the nay sayers - it just involves some time investment on your part and some good decisions.