I love Conjurer's Calling! And I just pulled a Khadgar, so I decided to make a hybrid. Carried me up to Rank 8 so far, and it's fun. Needs a bit of work, though.

Mulligan

Basically, play like a normal Secret Mage. There are a couple different cards in this hybrid deck that you'll need to take into account, though. During mulligan, always keep Corridor Creeper if you can. It only gets cheaper while it's in your hand, so it's best to get a hold of it as early as possible. Sometimes, you can't start with it. So, here are some other strong options:

• Kabal Lackey. High value card during the early game when paired with a secret. Its low health makes it lose value during the mid game and late game, so it's better to play it early to help maintain board control.
• Arcanologist. A lovely card, truly. She's a 2-cost 2/3 that helps you cycle through your deck's spells so you can get to the minions faster. I cannot tell you how many times I've coined into her on turn 1. If I get a Kabal Lackey during mulligan and don't have a secret to go along with it, I'll coin, play her, and then play Kabal and the newly acquired secret on turn 2. Now, is this a good idea? Don't know. Does it work for me? Almost every time. That's just so much value for only 4 mana.
• Mad Scientist. A staple in most secret decks. He's similar to Arcanologist in that he helps you get your secrets out of your deck and into the field. This kind of cycling is really quite helpful.
• Kirin Tor Mage. A solid card. For the same cost as a secret, you get a 4/3 on the field and a secret. Arguably, she is a better card to coin than Arcanologist.

Even though it's my favorite part of the deck, I would not recommend holding onto Conjurer's Calling. It actually feels too slow at the start. You can usually pull it later via Arcane Intellect, and Mad Scientist and Arcanologist help you thin out your deck.

Conjurer's Twist/Strategy

When everything goes right, your "high cost" cards will actually cost close to 0 mana to play. This will allow you to hit them with Conjurer's Calling once or twice in a single turn. Ideally, you want to save both Conjurer's Calling's for the Corridor Creepers, but Kabal Crystal Runner is also a decent choice when in a pinch. Since she's a 5/5, you'll probably want to try and swing at least once before sacrificing her, though. When mixed with Conjurer's Calling, Khadgar will easily fill your board. So, again, be careful. He absolutely multiplies the value of that card. This makes for fun combos, but a board full of minions can also limit your options.

Challenging Match-ups

This expansion has really, really brought out the Rez Priests, Token Druids, Evolution Shamans, and Murloc lovers. These can all become problems pretty quickly. When running this deck, Rez Priest is pretty much cancerous. I have no idea how to play around those taunts without adding them to the Priest's rez pool. Best of luck to ya.

Edit 6/5/19: You do not know pain until you've fought a SN1P-SN4P Warlock. Mechs have gotten buffed across the board and SN1P-SN4P + Mechwarper + Summoning Portal is currently broken. It's a pain is butt to get past mechs if you can't kill the taunts. So, you need to maintain board control for pretty much the entire game in order to best a Mech deck. Prioritize killing minions so your opponent can't abuse the magnetic mechanic.

Board-filling/token decks are less of a problem, however. Since the deck doesn't have any guaranteed wiping spells, you need to deliberately choose between killing minions or smacking face. If you have Ice Block in play, you have a little more leeway. You can essentially race to the finish. But! If you don't, you may very well lose that race. If you need to get rid of minions, make sure you do it BEFORE they get buffed by your opponent. Easier to kill a 1/1 than a 3/3. Try to plink em with your hero power instead of swinging at them with your minions. You really want to keep them alive if you can.

With little to no effort, taunt-heavy decks can become a problem. Your win condition typically involves smacking face with a lot of hard-hitting minions. Can't do that very easily if there are taunts littering the board. Your best answer to enemy taunts is usually Explosive Runes or Mirror Entity. The former removes the threat, and the latter gives you an exact copy of that threat. The trick here is timing. These cards are not reactionary. I would recommend using Explosive Runes towards the beginning of the match if you want to keep their side clean. I lean towards using Mirror Entity when there's more mana available to your opponent. Generally, I rather get a copy of a 5-cost or 6-cost minion than a 2-cost minion.

Edits:

Edit 6/5/19: Found that the deck was still hurting for damage and was moving too slowly when up against the hoard of Murloc Shamans out there. Made a number of changes to compensate. Dropped Stargazer Luna and Aluneth. Stargazer Luna doesn't seem to get enough value in this deck. At most, I get 2-3 cards pulled from her. Aluneth has the opposite effect. I can't seem to empty my hand fast enough to avoid burning cards. At the end of my deck, this weapon has actually killed me in some Freeze/Exodia Mage matchups. And 6 mana is too high a cost for this deck at the moment. You pretty much have to dedicate a whole turn to playing the card. A bit too slow. Arcane Giant was dropped for the same reason. Takes too long to get him cheap enough to play.

Additions: I added another Medivh's Valet and Ice Block. Valet for damage and Block for that extra round. Also traded the one Fireball for two Forgotten Torches. That trade alone gives the deck an additional 12 points of damage. I've definitely noticed the difference.

Edit 5/25/19: The deck has been playing rather well! Tried mixing up the deck, but the best results have actually come from Explosive Runes. This secret easily feeds Corridor Creeper if you have one in your hand. Plus, it helps maintain board control while also damaging your opponent. It's truly fantastic. So, I swapped out Forgotten Torch for a second Explosive Runes.