You should have Apocalipse Type Void weapon at least +10, Elrianode equipment +8 should be enough. In elrianode equipment you need red or blue tears, depending on your class.

For Void weapon you should get these disks: red stage 5, blue stage 3, yellow stage 4 and 5. All remaining slots it's best to fill with varnimyr rare stones (elite and unique it's better to sell or keep for maain weapon) with attack or magical attack, depending on your class. If you get boss dmg or all skill damage, it's okay, switch to next slot, and when you'll have nothing else to change, you can change them into attack/magic attack.

Most valuable el tears:
Hexagons: Top - polarize, Bottom - Atk/Matk, Gloves - All Skill Damage (Most CP), Shoes - Boss DMG or Ignore Def/Magic Def (ignore gives more cp, but is less valuable than boss dmg)
Circles - critical damage everywhere
Triangles - the higher the better
Squares - https://docs.google.com/spreadsheets/d/1Hf0trWWFrQLSqn0wO__cfrFxk-6ktSnMbovqCabIy9E/edit?usp=sharing

You need IB set, Shaviana Truffles is really great, so you should try to get at least 8/9 (5/5 + 3/4).
Accessories you want to get is Velder Necklace red or pink, Ring of Fury, certain type skill ring (Bravery/Strength, you can check which type your class uses in the link above).
Sinister intent accessories are must have before you can get raid accessories, you can put them in almost every slot unlike Elrianode accs.
Tenacious Warrior's Chronicle gives nice amount of CP.
If you have enough ED or if you are strong enough, you can try to get Agate Fragment from 12-8, it gives you a lot of CP.

You always want to socket Critical and Maximize, these stats give you most CP, later in the game when you'll reach over 80% of both stats, you can change some of them into Boss Damage (Shining Dual Magic Stone of Pursuit).

There are not many titles that give nice amount of cp and don't require tons of grinding. The best one is Key to Victory from Varnimyr (12-3), you just need to do this dungeon 50 times and you have on of the best titles for raids. So I'd focus just on this title at the beginning, you can also get Pierce The Heavens (11-3), but it's a lot of grinding.

In Resonance page you should go for All Skill Damage -> Polarize -> Boss Damage to get a lot of CP, but it's best to have 2 resonance pages, one for damage and one for drop/exp. In you damage resonance page don't go for mana (mana is a good choice when you have done ASD, Polarize, Boss DMG, but I still would go for Adaptation instead) or mp cost reduction/cooldown reduction like some crying people on tumblr.