I’m playing this:
Creatures
Lone Rider/It That Rides as One - First strike, Lifelink. Trample once transformed. This is the best card in the deck. I’ve won many games playing no other creatures.
Smuggler’s Copter - Card fixing, 6/6, flyer that is cheaper when you play other creatures. Mostly here for coalition events.
Solemn Recruit - Double strike, 3/3, for 6.
Visionary Augmenter - Fabricate 2, which pumps Lone Rider, and causes it to transform into It That Rides as One on turn two. Also nice just about any other time for the two +1/+1 servos it makes.
Spell
Declaration in Stone - Creature removal
Uncaged Fury - Grants double strike and +1/+1 bonus.
Unlicensed Disintegration - Creature removal, and usually 3 damage.
Support
Always Watching - Vigilance, and gives a +2/+2 to non token creatures you control.
Hixus, Prison Warden - Lock down on creatures which attack you.
Oath of Chandra - 5 damage to target creature, or plainswalker upon entering, and 2 damage to the planeswalker for every non-token permanent you play.
Sideboard
Blood-Cursed Knight - Replaces Knight of the White Orchid for events requiring vampires.
Gideon’s Reproach - Replaces Declaration in Stone for events requiring no spells, but not always.
Silverstrike - Replaces Smite the Monstrous for events requiring no spells, but not always.
Play
Ideally:
Turn 1 Lone Rider or Solemn Recruit, and overflow mana into either Visionary Augmenter.
Turn 2 Visionary Augmenter Play Hixus, Prison Warden if you have it, AND there are no adjacent 
gems, but I’ve recently taken to holding these until I have two to drop at once.
Turn 3 ramp either 
, or into other creatures, or supports. If your opponent has creatures out already (not likely), focus on Declaration in Stone, Unlicensed Disintegration, or Oath of Chandra to remove them, or Always Watching if you have any creature with First Strike.
Turn 4, and every turn there after, Stoneforge, Stoneforge, Stoneforge in between playing out more creatures, removal, and supports.
I have used Lithomancy only a few time, and it was in an event facing against a 400+ health opponent with a 2 or less creature challenge. I had a hard lock on all their creatures thanks to 2-3 shielded Hixus, Prison Warden, and was at 30 
. It was a long, slow grind, and I used it to dig for extra Hixus, Prison Warden, or other supports to trigger Oath of Chandra, and to have a full compliment of fully charged removal on standby if Hixus, Prison Warden got destroyed. Harbinger can be a game ender, but you should probably not use it in other situations unless you’re using It That Rides as One to Trample down a defender.
Weaknesses:
Flying, Hexproof, and big Tramplers prior to you getting Vigilance and Stoneforge online with. Focus on either direct removal, or lockout and defending Hixus, Prison Warden.
Strengths:
Strong against mana draining, and discard. Very resilient, consistent, and cheap. Control/discard decks don’t do much since most everything is cheap. Keep a card in second position for them to drain/discard, and move the spell you want to cast this turn in first position.
Improvements
If I pull them, these are the cards I would put it right away:
Angel of Invention - Flying, Lifelink, Vigilance, Fabricate, gives each creature you control gets +3/+3, and an 8/8 body for 18. Replaces Oath of Chandra because its a beatstick, and superfriend.
Gisela, the Broken Blade - First Strike, Flying, and Lifelink, and an 8/8 body for 12 mana. Replaces any creature except Lone Rider/It That Rides as One because it plays turn 1, and has Trample. Best card in the the game.
Inner Struggle - Replaces Smite the Monstrous, but I have no luck pulling this. One of four uncommon SOI cards I do not have.
Olivia, Mobilized for War - Flying, Haste, Lifelink, and an 8/8 body for 20 mana. The discard trick for any incoming creature after (and including) her gives that creature gains +3/+3, Flying, Haste and Lifelink. Superfiend standout.
Scourge Wolf - First Strike, with conditional Double Strike, and a 4/4 body for only 8 mana.