1) How do I sell items? I visited the trader in Riverwood and a pop up appeared telling me stuff below the line can be sold. I have plenty in my inventory but only a Buy option.
2) Is there any combat advantage to being on the higher ground?
3) Is there a basic combat tutorial anywhere? I see the Favorites...is that the equivalent of Weapon Sets. I want to switch between weapons and spells quickly.

Thanks

Wow... Surprising number people having trouble with this. You can only sell items to merchants who sell those particular items. Armor/weapons to a blacksmith, ingredients to alchemists etc. You can sell anything at pawn shops though.

2) Not to my knowledge. I find it harder to hit archers who have that advantage though.

3) Pretty sure there isn't. Favorites are used to quickly access certain items so yeah, you can use it for pretty much any item.

Scroll down past your character's name to your carried items.

But I strongly suggest you RTM (Read The Manual).
Enjoy.