The NPC's are usually close enough to the wall that this is possible

In order to face someone, you can hold Battle of the immortals Gold down the ctrl key and try to attack them. This will cause you to face them.

Another way to do this is to hold down the shift key and right-mouse click on the person you want to face. To truly face the person, right-click on the feet of the person as this is where they are standing.

There are certain zones in the game called Combat Zones. These are found in Doorways, at the ends of Bridges, and in a few other areas of the game. If you are in one of these areas, someone can kill you without penalty.

Somewhat related to the previous tip, you can talk to a NPC from outside of a building. This means you don't have to walk through a Combat Zone to purchase or sell items to the NPC. The NPC's are usually close enough to the wall that this is possible.

You are only allowed 100 items in storage. This may seem like a lot and you will never get there, but you will. When it gets full, it is usually time to sell stuff.