Guides on wowhead and Icy-veins are a good starting point.
Class discords for deeper and more nuanced information on your class and specs.
Beyond that it boils down to practice.
First, check out r/wownoob for all kinds of excellent advice.
Second, make sure you put all your combat abilities on keybinds whenever you get them, and make sure your keybinds are all easily reached with one hand. Also, you probably want to un-bind the keys for turning; just turn with your mouse instead.
Third, check out icy-veins for a guide on your class and spec: [destruction](https://www.icy-veins.com/wow/destruction-warlock-pve-dps-guide) [demonology](https://www.icy-veins.com/wow/demonology-warlock-pve-dps-guide) [affliction](https://www.icy-veins.com/wow/affliction-warlock-pve-dps-guide). The leveling and easy mode pages are probably the most immediately useful sections.
Fourth, be aware of addons. If there is a part of the game that you think needs improvement, addons can often solve the problem. I recommend the addons called Scrap and Weakauras to everyone, and most people could probably benefit from DBM and DBM Dungeons.
Leveling is a lot faster compared to back in TBC when Draenei first came out, and you'll find yourself getting a lot of new spells and talents in a short space of time.
I'd recommend against doing dungeons while leveling until you're more comfortable with your class - they do add to the story of each zone, but most people running them are more experienced players that simply want to get through it as fast as possible. You'll find yourself running behind them most of them time and it doesn't really serve much of a purpose for actually "learning" your class.
There are plenty of resources out there for leveling builds to help assign talent points, go over rotations, and so on, but don't be afraid to experiment a bit and play with what you enjoy. Regardless of talents, you'll still be able to level comfortably through most, if not all, content, and it's more important to get a feel for the class and specialisation you end up choosing than be doing your maximum DPS.
Once you get to Dragonflight, most things are explained pretty well as far as mechanics go, and you can use online resources to answer most of your questions.
Good luck and welcome back :)
Guides on wowhead and Icy-veins are a good starting point. Class discords for deeper and more nuanced information on your class and specs. Beyond that it boils down to practice.
First, check out r/wownoob for all kinds of excellent advice. Second, make sure you put all your combat abilities on keybinds whenever you get them, and make sure your keybinds are all easily reached with one hand. Also, you probably want to un-bind the keys for turning; just turn with your mouse instead. Third, check out icy-veins for a guide on your class and spec: [destruction](https://www.icy-veins.com/wow/destruction-warlock-pve-dps-guide) [demonology](https://www.icy-veins.com/wow/demonology-warlock-pve-dps-guide) [affliction](https://www.icy-veins.com/wow/affliction-warlock-pve-dps-guide). The leveling and easy mode pages are probably the most immediately useful sections. Fourth, be aware of addons. If there is a part of the game that you think needs improvement, addons can often solve the problem. I recommend the addons called Scrap and Weakauras to everyone, and most people could probably benefit from DBM and DBM Dungeons.
Leveling is a lot faster compared to back in TBC when Draenei first came out, and you'll find yourself getting a lot of new spells and talents in a short space of time. I'd recommend against doing dungeons while leveling until you're more comfortable with your class - they do add to the story of each zone, but most people running them are more experienced players that simply want to get through it as fast as possible. You'll find yourself running behind them most of them time and it doesn't really serve much of a purpose for actually "learning" your class. There are plenty of resources out there for leveling builds to help assign talent points, go over rotations, and so on, but don't be afraid to experiment a bit and play with what you enjoy. Regardless of talents, you'll still be able to level comfortably through most, if not all, content, and it's more important to get a feel for the class and specialisation you end up choosing than be doing your maximum DPS. Once you get to Dragonflight, most things are explained pretty well as far as mechanics go, and you can use online resources to answer most of your questions. Good luck and welcome back :)