Interactive elements

Interacting with stuff in game makes it that much better.

A example of a bad interacting system is pokémon. When you went to read any book there was it would say "Books full of pokémon stuff."

An example of a good interacting system is terriamanga. Books would range to pointless info to vitally important knowlegde.

Not just books, but treasure chests, characters and more.

The more difficult a treasure chest is to get, the better the item is. (in theory)
A fortess is going to have more bounty than Jim's house.
NB. Not all treasure chests have to include treasure, try to keep the player on thier toes...

Characters can interact.

Use a question or two with characters.
E.G. What do you want to know about?

Money
Dragons

Try to keep involving the player in the forwarding of the plot.

Try not to give the player a choice when they can only do one thing any way:-

"Do you want to go left or right?"

And you choose left.
"We really ought to go right."
I still want to go left.
No, we are going right whether you like it or not, so really I shouldn't of asked you.

Cause it should be:-

"Do you want to go left or right?"

And you choose left.
"We'll go left then but right would be easier."
I still want to go left.
"Fine by me."

Not everything has to be interactive but if you don't put some in the player will soon quit bothering to check bookshelfs etc.

Resulting in not as good of a RPG for the player.

Remember:- It's your RPG so just make it so you like it, and therefore other people like-you will also like it.