Project managers ask me all the time to give them the magic beans, the ingredients or formula that will guarantee a successful project. It is asked perhaps not quite in these words, but you get my meaning. What is the secret to guaranteed success? I tell them this, there are no magic beans. Some beans will grow in some places, some will grow with a lot of prodding and attention, some will drown in boggy water but there are no beans that sprout and thrive everywhere.
Project management is part science and part art. There are certainly PM methods that work generally well, but not every method works equally well on every project. The trick is to apply the best methods to a particular project based on the context of the project. This takes a nuanced understanding of PM techniques and experience to know what fits and where.
Strong planning and assigning small chunks generally works. Lots of tools help. Effective governance.
If there are any magic beans, I would say that the most important attributes and things that need to go right on a project are to have a productive and mature project environment, a highly skilled project manager with specific domain experience, an effective governance model and a high level of velocity. If you can get those pieces right, you have improved your chances of success.