(1.) Ball striking.
Ball Striking is critical. You need to be able to keep the ball in play and hit fairways and greens consistently (above 45% on each IMO)... You don't need to be long to break 80. But you need to be consistent and have tighter dispersion to prevent yourself from hitting into hazards and other junk that causes double bogeys on the card.
I hardly practice with my driver... I usually am hitting a lot of irons and focusing on my full swing (5i/6i/7i). This has helped me learn a swing that can get me around the course and put me in position to score.
If I'm inside 175yds... I really feel like I will have a legit look at birdie. And at least get it near the hole - or somewhere on the green.
(2.) Short Game.
Once you get on or around the green - you need to be able to get the ball into the hole. Therefore, Pitching / Chipping / Putting aka Short Game is key... Turn Bogeys into Pars with a quality short game by getting up and down. And I can't tell you how many times I've birdied Par 5's where I was able to get up and down leaning on my short game. It is a big part of being able to score and prevent bogeys.
(3.) Right Mental Attitude.
Breaking 80 isn't hard. But you have to have the right mindset. Confidence in your game is huge. Knowing you can hit the shot is one thing. Doing it is another. You have to believe in yourself - because really - no one else will on the golf course. It is in your hands to execute the shot. And you gotta have the right mind to do it.
Get golf instruction. If you don't know what you are doing... You're going to waste a lot of time working on bad habits. Or just wasting your precious time and money. Go and get a lesson from a reliable source that knows the game of golf. Someone that is recognized within the industry. Or at least someone that has a list of references and sources that they are a legit instructor. Once you find that instructor - take their teachings as if it is doctrine. Live by it. You have to digest it and believe it before you can act.
(5.) Hit Balls - Play, Play, Play, Practice, Practice, Practice.
You need to hit a lot of golf shots to learn how to score and play. Go play the course, spend time at the range, or even invest in a home /indoor setup. The point of the matter is this... You aren't going to get better by sitting on your couch watching TV - or farting around on the web. Get your hands on a golf club and practice making swings. Taking divots. Hitting balls. A golf swing needs to be fine tuned to where it becomes an unconscious move. One that you can execute in front of your friends. One that you can execute in front of strangers. One that you can execute when skins are on the line.
If you dedicate yourself to the game... Breaking 80 is easy. The problem with 98% of the world is that they want to take an easy route. The game of golf has no short cuts.