I believe that wrestling success comes from being strong in what I will call the "four pillars of wrestling".
The four pillars of wrestling are: technique, training, diet, and mental toughness.
First, a wrestler needs to have excellent technique in order to succeed. Conditioning can take a wrestler far, but good technique is important above all else. I had a professor in college who told us he had a simple formula for doing well on his tests. He simply said, "Know everything." The same applies to wrestling--know everything. You won't use everything, but you should know everything.
How many ways are there to set up a double leg or a single leg? Hundreds? Thousands?
Looking back at my high school career, I'm not sure I ever did a stand up correctly. I would try to clear my left arm by throwing it up against my face as I stood up. I wasn't that successful at stand ups which are an absolute essential move to be good at to succeed in wrestling. I should have been bringing my left elbow tight to my side to block his hand while bringing my body straight up. I should have worked hard at hand control and breaking his grip. I could have gotten a lot more stand ups by knowing a little better technique.
I never heard the term hip heist during the time I wrestled. Even during my college years I never heard the term. Of course, I knew how to do a switch which involves a hip heist. But, I don't remember ever being taught a hip heist except as part of a switch.
I never learned how to do a spiral ride. Why is that?
I was always taught to never put a half in if your opponent is on his hands and knees. But, now I know you can put a half in even if the other guy isn't broken down as long as you block his leg on the opposite side and as long as you're not directly behind him.
The bottom line is that you should know every move possible and the best way to execute it. Hopefully, you have a knowledgeable coach. But, you can also look at books and videos that will show you proper technique. Even if you're short on money, youtube.com and themat.com have some very good wrestling technique videos you can watch for free.
Second, a wrestler needs to be well conditioned. He needs to train hard. Lift weights. Drill hard. Wrestle hard. Work out year round. Don't just be a three or four month wrestler. Check the articles here on conditioning and training. Remember that wrestling is primarily an anaerobic sport. You don't have to run (and shouldn't run) five miles every day to get in good condition. Google Zach Even-Esh and Matt Wiggins and see what they have written about training for wrestling and mixed martial arts. The great Karl Gotch said, "Conditioning is the greatest hold." Being in great condition could be the deciding factor in a match. You need to be able to wrestle that full six or seven minute match and possibly overtime as well.
Third, a wrestler needs to watch his diet. Many wrestlers have to "cut" weight. Even if you don't cut weight, you should try to fill your tank with good fuel. If you are going to cut weight then learn to do it right. Read my article on cutting weight and look it up on the internet and get yourself educated. A wrestler who is weak and dehydrated from starving and restricting fluids is not going to wrestle well.
Finally, a wrestler needs to have mental toughness to succeed on the mat. Look at my page on mental toughness. Read articles on sports psychology and mental toughness. If don't walk onto that mat in a focused state of mind you are in trouble.
Some people might add the support of family, friends, and fans as another pillar. That's a valid point. A coach who is has the technical expertise in wrestling is also desirable. A coach needs to be tough at times but not a jerk. A coach needs to be supportive and motivating. Being a good coach can be a tall order. But, a good coach can make a huge difference. If your coach isn't providing all that you need then seek out other wrestlers and attend wrestling clinics and camps.
In conclusion, the four pillars of wrestling that need to be addressed in order to reach success are technique, training, diet , and focus.