First you just want your regular! This on if 9 by 13 blocks.
Then you want to dig a hole three blocks away from the door, that is three blocks deep and two blocks down.
It should look like this, make sure it is three blocks away from the house at all angles and sides.
Next you want to take your Obsidian and make it four blocks wide right at the entrance.
Then you want to cover it like a shelter, build it three blocks up so there is room for the two Iron Doors. On each side leave it open.
Then you want to put two iron doors on the outside. DO NOT PUT IT ON THE INSIDE, unless you want to. After you put your two doors put your buttons on the outside and inside, to open them both ways.
Now start to put the your lava one block up all round the house in the hole.
Your Lava should look like this. Looks pretty cool, right?
Your almost done! You now want to put Cobwebs on top of the lava, to trap the mobs!
It should not look like this! Make you get every spot with the Cobwebs!
Last step is to take Iron Bars and place two up around the whole thing!
This is one of the most effective guard that I have made for my houses! Hope you enjoy!