The first thing to learn is basic tactics... pins, forks, skewers, guard destruction, deflection, and so on. Then learn how to put those elements together into "combinations".
Model Mates are next. Practice typical mating patterns such as the corridor mates, Lolli, Greco, Damiano, Anastasia and Morphy mates.
Then study some simple endgames... King and Pawn endgames are the best to start with, then King, Rook and Pawn engames.
After that, you will have the tools you need to take a look at typical middle-game strategies and opening theory... those subjects should be deferred until you've gotten a decent grounding in tactics, mates and endgames.
So how can one get one's rating to 800 USCF/FIDE? I'm not talking about on the internets.
What kind of skills does one need to master? It is a lot harder than it looks. Even people on here are rated like 300-500!