I have maps for these also here: http://www.xbox360achievements.org/forum/showpost.php?p=2114...
You must find all 3 spell stones, 3 Forge Stones, 6 minion command upgrades, 5 Mana upgrades, 5 Health Upgrades, 9 spell catalysts and one Harp. You can see your Mana/Heath upgrades by your throne, the command upgrades in the minion burrows and your spell catalysts at the spell upgrade station in your bedchambers. Most of these are pretty hard to miss as they are generally in plain view, a few are off the beaten path though and require you to backtrack with new minions.
Unique item found on Nordberg Sanctuary,fairly near the end just before you reach the second Netherworld gate and have to use the second minion control stone to raise the lift. Hard to miss.
Health upgrades (5)
* Nordberg – Just before you go into the first netherword gate, behind a wooden blockade where you kill/dominate your first townspeople.
* Everlight Reef - On the northernmost small island, carry the item to your ship and transport it to a nethorworld gate.
* Nordberg - After you get the blue minions return to Norberg Gate 2 and grab 15 or so, then out the northern gate of the town. Turn right and walk down to the water, past the seal spawning area. Select the Raft with LT and send the Blues with RT, press A to activate it and LT/RT to move forward and back, dock at the port to the left (hit B) and retrieve the upgrade. You'll then need to sail it back to the shore and carry it to a netherworld gate.
* Wasteland - You'll need blue minions to advance this deep into the wasteland. From the first netherworld gate follow the path and pass through the area blocked by two magic goop piles, you'll comp across a human survivor village with a few minion burrows. Activate the minion-wheel and continue on to the next village. Here the Heath object is to the south through a goop pile with two ruined buildings leaning over it and constant slugs spawning. This is in the north-eastern part of the Map. Sweep your blues through the goop using RT to clear and path and grab the object.
* Empire Hills - After the second catapult battle you'll come across an area with 6 bombers. The Health upgrade is in the opne just behind them, very hard to miss.
Mana Upgrades (5)
* Nordberg Sanctuary - After you destroy the huge statue of Queen Fay a large blue crystal will drop. Destroy this and inside is your first Mana upgrade. Almost impossible to miss.
* Everlight Temple - After beating the Spider Boss and ascending the lifting using your spider minions this upgrade is directly ahead above the Netherword gate. Head up the stairs to the left of the gate and then go right to pick it up.
* Nordberg - Return to Nordberg when you have the greens. Head to the middle of the town, over on the western side is a poisoned barrier, send the greens to attack it with RT and continue on. The Mana upgrade is on your left as you follow the path around, close to a gate you can open using the nearby minion wheel.
* Wasteland - You only need your Red Minions for this one. From the Netherworld Gate head down the path to the first open area and take a left (heading west) there is a path down to an area with jets of flame and the Upgrade. Sweep your reds through the path to collect it.
* Wasteland Sanctuary - During the Salamander King fight you'll come to a point where you must activate three bridges using 1-minion switches. This Upgrade is down a path near the third switch (the one that activates the bridge over the water) This is just north of Netherworld Gate 2 in the region. You'll need your blues to get it out of the water.
Spell catalysts (9)
* Nordberg Commune - After you use the wolves to enter the commune the catalyst is behind a barrier to the north which requires reds to break down.
* Everlight Temple Outskirts - You'll come to this map after the Everlight Facility. Continue on and, after the fight with the empire soliders being attacks by spiders by a large blocked gate, turn left. You'll fight a couple of "Vacuum" enemies and the catalyst is hard to miss in the large open area they are found in.
* Everlight Town - You need the Blue minions for this crystal, so return only when you have them. From Netherworld Gate 1 (The one in the area that had the Boss fight and contains the Governess and Treasure Chests) head out and take the left hand path, this will bring you to the Beech. Keep left and cross the water to an island, the catalyst is in plain view in the center of it. There is also a Dark crystal  along a minion path to the south of the island if you have yet to pick it up.
* Empire Heartlands - After defeating the Gargantuan and clearing the roads of Sentinels you must enter the Villa to find the sedan chair. This catalysts is to the left as you enter the villa, hard to miss.
* Empire Sewers - In the water behind the Region's Netherworld Gate, return here when you have the blues to pick it up.
* Wastelands - You need the Green minions for this one. From the Netherworld gate head down the path until you come to the first large open area, head right (east) and you'll come across a ruined halfling village with some jets of poison gas guarding the catalyst. Send your Greens in with RS to collect it.
* Wastelands - Deep in the Wasteland (you'll need blues). Following Florian to the Tower Heart Shards should bring you to this one, hard to miss. It's in the southern Area of the magic blue goop lake, up a set of stairs in an area with a ruined building.
* Wasteland Sanctuary - After you charge the Tower Heart at the first crystal and fall through the floor take the right hand fork in the path and this catalyst will be right in front of you, hard to miss. It's south of the first Netherworld gate (the left hand fork takes you to this)
* Empire Hills - Just after the first catapult battle this catalyst is down on the right, just past the bridge, in the area the Empire Formations were. It's guarded by a Gargantuan and Empire reserve tent.
Command upgrades (6)
* Nordberg – Just after you get the first spell, can’t miss it. Make sure you don't take this into the Netherworld gate until after the cutscene or it will gitch leaving you with no object and no command upgrade making a few achievements impossible.
* Nordberg - After you clear the digsite and unlock the mining cart to destroy the Nordberg gates you will run into some archers on a hill, just below that are some rocks hiding this upgrade. Kill the archers and stop the cart beside the rocks, put your reds on a guard marker next to it (hit Y) and they will automatically target the cart, destroying the blockage.
* Everlight Reef - First you'll need to obtain the elven ship with the ram on the front (this happens through story progression). Next you need to sail to the rock blockage which is just south of the northernmost gate on the center island. Take a run up and tap A for ramming speed to break through. Dock the ship at the port and carry the item on board with your minions, you'll now need to sail to a Netherworld gate with it.
* Everlight Town - When you first enter Everlight town to clear out the Empire this Upgrade is almost directly on the path you must take through the various locked gates, just after destroying the two empire tents and where Gnarl comments about being where the elves live. It's in front of a locked gate (which later allows you into the Elf rebellion sidequest area) in the Northernmost part of the town close to Netherworld gate 3 (To the right as you exit the gate). Very hard to miss.
* Empire Harbour - Straight ahead and slightly to the left from the only Netherowlrd Gate in the region. Again, very hard to miss.
* Wasteland - After the large rotating stone platform, and just past netherworld gate 2, is a Zombie village made of halfling holes. The final command upgrade is behind a breakable barrier which blocks the exit to the north side. Almost impossible to miss within the story progression. Dark Crystal  is underneath a tent right beside this, be sure to pick it up at the same time.
Spell stones (3)
* Target (Nordberg) – This is the first you get, the game walks you through it early on in Nordberg and it’s unmissable.
* Halo (Everlight Jungle) - After you get your green minions return to the nethorworld gate, there are two green poison barrier blocking your way that you can now get through. One leads to the next area, the other to this spell stone.
* Minion (Wasteland) - You can get this spell stone as soon as the Wasteland becomes available, no special minions required. Simply follow the path around from the Netherworld gate and it's directly ahead in the first large open area. Almost impossible to miss.
Forge Stones (3)
* Nordberg - After you get the red minions and return to conquer the town this is behind the first fire barrier you come to, just after your first fight with a Centurion and an Empire formation. Very close to where you got the first health upgrade.
* Everlight Jungle - Just after you find the Netherworld gate, this stone is down around the corner from the two green poison barriers sitting in front of the mother godess statue. Almost impossible to miss.
* Empire Harbour - After disguising your minions and entering the fort with the catapultthis stone is up the stairs right beside the catapult, almost impossible to miss. Dark crystal is also in this area on the ground floor.