Use the FBA model- One of the main advantages to use Fulfillment by Amazon (FBA) is that it hugely increases your chance of winning the Buy Box.
Go with Competitive pricing-Pricing is one of the most important factors to win the buy box.
Provide fast shipping -A seller who provides fast shipping has a higher percentage of winning the buy box.
Maintain the stock level
Maintain Account Health
Maintain Positive Feedback