As with all the other "Adept --" trophies you'll need to get Cheryl Mason to Level 10 on the Bloodweb to unlock 3 perk slots. It's easier to grind out Bloodpoints with the Killer considering you don't necessarily have to sacrifice all Survivors to gain Bloodpoints but can at least gain more by chasing and hitting survivors. I found the Doctor to be the easiest one to grind out Bloodpoints as you can just hit the survivor with his Electroconvulsive Therapy attack to earn them (so just spam away).
To get this trophy you need to escape a match with Cheryl's 3 unique perks in the slots including: "Soul Guard", "Repressed Alliance", and "Blood Pact". Don't assign anything else if you already leveled her up to 15 and don't give her any items or offerings. Another thing, don't pick items out of chests in the maps as that will count as using something else to assist in the escape and won't unlock the trophy. You may open the chests to count towards the "Looter" trophy if you want but as long as you don't take the item you're safe for "Adept Cheryl".
I can't say that escaping a map is easy, depends on who you get as a Killer; some Killers play to win (can be really good or newbies) and some are grinding away for Bloodpoints like how I said in which those tend to let you go. Sometimes you get a really good team that works fast on generators and picking people off the hook OR, if your team is wiped out leaving you, you'll get lucky finding the hatch the opens when you're all that's left and can happen upon it. The Killer might find it first, close it, and, if you're lucky, you'll be able to open the escape door in time to slink out.
Cheryl's perks are pretty good for the end game, as "Soul Guard" will assist in running faster towards a door if you're pulled off the hook and someone has gotten the escape door open. It also helps if there's a Hex totem on the map that's affecting you and if you're downed you can crawl to a hiding spot and pick yourself up, kind of like Bill's "Unbreakable" perk but infinite as long as the Hex totem is active. "Blood Pact" will dramatically decrease the odds of being Obsession, increasing your chances of survival and can also assist you in seeing the Obsession (and vice versa) so you two can help each other out. It also gives you both Haste if you or them have begun healing one another, so you can flee fast if the Killer spots you. "Repressed Alliance" is good for blocking a generator from getting kicked by the Killer if they come around, there's also a lot of Killer perks that help them to regress the generator repair so it assists with blocking those, too.
Good luck with Cheryl! "Don't you think blondes have more fun?"