I agree with @Ryan Cox: the best strategy is the one that works for you!
What fitness routine produces the best results? Cross-fit? Running? Swimming? Yoga?
The truth is, the one that you most enjoy and stick with. I know investors that love to self-manage and fix leaking toilets. Other managers like to buy and hand off to a property manager so they can spend their time skiing or looking for the next deal. Some like to be constantly busy while others like to chill on a beach as much as possible. Some prefer single-family homes while others swear by multi-family or commercial.
You have to decide what is important to you, what suits your personal style, and then find a niche that fits your personal style.