Hey guys. I made a little while ago a
indoor mapping tut. It's a little bit rough
but i hope you get the basics XD
At first we only need Tile A!
Step 1:
First, set the basicwall of the house.

(in this example i use a doublewall. But you can also just use a singlewall or surround it
by a black Corner. The one with the black Corner is very great btw.)
Step 2:
Now the real wall. Here i recommend setting it two tiles long.

Step 3:
Next the floor.

Here you can choose whatever floor you like. Allthough it should match with
the rest^^ (don't take the Lava or something xD)
Step 4:
After that i'll make some rooms indoor. Just use the basic wall and
seperate some parts of the map with it.

Step 5:
When this is done, you can fill it a little bit with various things you can find
on Tile A. Like a carpet or some tables.

Step 6:
After your done with the Basicindoor you can switch to Tile C for indoor stuff.
Now you can decorate it with the things you'll find here.

Now this house has some Windows, Shelves and a Picture.
In this example i tried to craeate a typical house.
The left part is a Livingroom/Kitchen and the Right part a Sleeping room.
(You can also make the gap to the Sleeping room smaller^^)
Final Step:
When you're done with everything you can now decorate you're map with some NPC's.

You can also make things interactive by setting some events on different things
like the picture. ("Oh what a nice picture") xD
btw. I know that this map is a little bit empty. But you can always fill it
with things or just make smaller rooms^^
I hope you get the basics. Btw.
here is an example of a map by me with Black Corners:

(actually i like the last map better then the one in the tutorial^^)
I hope you like the tut.
If you have critic or suggestions then pls post it here or
send me a PM.