Here is a step by step inspired from the statues that I made for my fortresses. You will need:

Cobblestone
Stone Bricks
Stone
Stone brick stairs

Step 1: Foundation

First place a 5x4 stone layer on the ground, followed by a surrounding 5x4 layer of stone brick.

Step 2: Cold Feet

Place 2 stone brick stairs on the second column of the 5x4 stone foundation, and flesh it out by placing a stone brick behind each foot.

Now each stone type represents a different armour piece
STONE = Metal
STONE BRICK = Plate Armour
COBBLESTONE = Chain Mail

A 2x1 cobblestone tower, and connect them.

Step 3: Real Thighs

On the back of the maille trousers, add standard stone around every cobblestone.

Step 4: The Real Belt

Add 3 stone bricks across the cobblestone to create a sort of belt, and thicken it from behind with stone.

Next add 2 stone stairs to either side of the belt and add 2 stone in between.

Step 5: Complex Bodies

Now here's the tricky part, add 2 cobblestone to the stone layer in between the stairs. Add 2 stone to either side of that.

Add onto those stairs with 2 stone bricks, finally adding 2 stone stairs on top of that. Do that to both sides, and fill the In between places with stone.

Step 6: Big Heads. Big Noses

This part is optional.

Add one stone brick to the highest stone layer, and then connect a stair piece face up.

Step 7: The Round Heads

First thicken the head piece with a stone brick behind the piece which connects to the stair piece. Then add a stone piece to the top of the the connected piece in front, and add another piece behind that.

Place 2 stair pieces above them, you may have to keep removing and placing them so that they are face down.

Step 8: The Other Round Heads

Repeat that process to the other side, and place another brick piece on top of the original connecting brick stair piece to complete the head piece.

Step 9: He's Armless

Now onto the arms.

Place one stone piece on each side to begin the arms.

Step 10: The Arms

Extend the arms with 3 cobblestone pieces, followed by a stone brick piece for the hands. Repeat this on both sides.

Step 11: S.H.I.E.L.D

For this shield, you can do anything to your own design, but for this design all you have to do is build out of the arm with stone and stone bricks, followed up by rounding the shape up with stone brick stairs.

Step 12: The Sword and the Stone

Again, you can do any design you want, but this spear/Halberd is made by building up and up with stones, tipping it with a stone brick, then build down onto the foundation .

Step 13: Finite!

There you have it, a complete statue.

Next Ible will be a non working catapult yet awesome looking :D used in the Citadel set I recently made.

Happy Building!