All of them, really. A wise person would never waste any source of information.
The path to becoming the best of the best in your class goes like this.
- Read every ability and passive and understand them thoroughly.
- Read online information and guides, from literally all sources to get a " rough idea "
- Practise your class on target dummies until you’re confident.
- Do some low level content to see how you fare in a real environment
- Watch youtube videos and guides especially in the content you’re aiming to play in
- Practice on target dummies
- Read indepth-complicated guides found on discord, forums, posted by pro players.
- Practice on target dummies
- Move through the levels ( normal/heroic raids, M+10s )
- Watch youtube videos of pro players
- Practice on target dummies
- Talk to pro players, either via ingame contact and or twitch gain info, insight, tips n tricks and see what they’re thinking
- Compile all the information and figure out the best approach
- Apply the approach by training on the training dummies.
- Slowly add your own style and thinking to your gameplay
- train on the training dummies for extended periods of time, until you feel like you’ve mastered your class
- Train on the training dummies until you feel like you can naturally play without being too absorbed into trying to do your rotation so you can focus on other stuff
- Start doing top tier content
- enjoy atleast epic/legendary logs
- Kick it up a level by theory crafting, thinking hard on how to act, how to improve, min-max and use the environment to it’s fullest and you’ll get pink logs or even top 100 ones.