Here are some suggestiions.
Experience noted, find people to play that are ranked higher and better than you. Become friends with them, know them, your influences directly play a part in how you play. Champions and consistent top cut people hang out with others of the same caliber. Like fish swim together. Here comes the list as you requested.
1. Play someone better than you. Play them till your eyes bleed. Find out why you might lose to them.
2. Learn to body language. People use tell-tell signs when they are having issues with their deck exploit that.
3. Improve your instincts, you currently have an idea of what to do and how to play. To become better, you must retrain your instincts to feel like maybe you aren't making the right choice which might cause misplays.
4. Be methodical. Throughout the TCG eras there have been similar decks that associate themselves with play-styles(Trap,Balls to the Wall,Conservative,Teched), try out many decks see what works for you. The best players know every card and every counter expect that. This is a chess match treat it like that.
5. Know the strengths of each card, for example Juniper is a "staple supporter" in most cases, people have recognized the top cards in each format and why they should use them.
6. Do research. Be obsessed. Like looking at other people's decks and figuring out how their combos work. propokemon.com is a good start and sixprizes.com
7. Inventing rarely works. Yes we all like to think we can come up with the best hidden crap in the game. No. Take your research know the top tiers of decks and each tier. Each tier ties itself to feasibility, skill, and consistency above all else.
8.Take a top tier deck that you like and make it your own. Modify the lines, see what you don't have when you need it most.
9. Practice with extremely skilled people with the deck from all the above and you will see improvement given the investment. There are always cheap decks out there, though cheap being roughly give a moderate amounts of success. Skilled players are also masters MASTERS at trading or they have money. Top decks are expensive because they work and there is demand to be better thus card prices are controlled by the demand and tiers that they are placed in.
10. Being the best involves instinct and drive to be better, ultimately it will be up to you how you use these ideas that I have given you, as an example, I took and bought someone's top deck when I started playing and played them till i beat them, I ended up winning the Cities Championship that year, have fun, don't sweat being the best, because its about who you are with and what you can learn. This game is strict, fun, and have really good players for the most part in our ranks. How you improve each week determines imo how successful you are.
11. Self Control comes with instinctual challenges, by playing better people you can figure out misplays even if they don't seem like it, because they are one, two steps ahead of your thinking process.
12. Lastly by knowing these top decks which are made usually out of what is called a "Barebone" thus their mechanics are the same, hence the strongest cards and top decks all have predicatable moves with tech"surprises" splashed in. This denotes half of the playing style.
Open your mind, if you care too much about winning you will win little and lose hard. Caring too much causes anxiety driven rage which is a problem. Don't set the bar high for your self, find your middle ground, if you do 3-3 at tournaments, expect using that same deck you will hit around 40% w/l ratio.
You want to make friends....trade...trade for losses... sometimes. If they feel like they are a good person go ahead, pay it forward. Not ridiculusly, but a favor here and there creates opportunity for someone to like you. Best conversation starter "Do you got any trades?"