While I can give a lot of credit to Marius, Sulla, Pompey, Scipio, Fabius Maximus, Hannibal, and some later generals, Julius Caesar was simply head and shoulders above everyone else. Here's why.
1. He was clearly an awesome strategist, diplomat, tactician, leader and of course, logistics & personnel manager. Defeated armies that outnumbered him, etc. Many generals are that, of course, so please read on.
2. He promoted his name, Caesar, to mean a government office that held for over 400 years.
3. He wrote, "Commentaries on War", which I believe most subsequent generals have read and learned. Read it yourself, it's a great work of propaganda and military information.
4. His war on Gaul, which had been a nearby and very major problem for the Romans for a century, was financed by himself. He controlled the government for one year, that got him started. He immediately switched to financing he had arranged while consul for one year, many thousands of $talents. He generated enough money and efficiency in Gaul that he continued for years, without funding from the Roman Senate -- that business set up the Crossing the Rubicon and so on.
5. Recognizing the problems the Romans had, and recognizing the solution would need to be larger than himself (and this is where he exceeds Alexander the Great), he willed a large sum of gold to every citizen of Rome to set up his nephew. This nephew was chosen by Caesar as the best, was willed the bulk of Caesar's fortune, was acceptable to Mark Anthony (another of Caesar's nephews and Caesar's trainee), and so young Augustus Caesar established an empire and peace that lasted, more or less, 400 years.
Bibliography. Start understanding Caesar by reading "The First Man in Rome" by Colleen McCullough, about Caesar's Uncle Marius. It's easy to grasp because she is a fine storyteller, accurate because she is read a lot (like Gibbon), and provides a useful Glossary. The bibliography of details, you can then find everywhere you look.