Cultivation must be long-lasting, continuously practice. When you can keep your heart stick to the cultivation, continuously practise without laziness, you'll succeed in Buddhism. Also being attach to worldly things, such as wealth, will cause you drop to lower realm. Below is a story about a monk who attached to money, greed on money. The monk after his death fell into the birth of a turtle. He requested his friend in the monastery to save him, using the money to do good deeds and offer to the Sangha.
There's another story about someone who recites "Maha Karuna Dharani" (大悲咒 - da bei zhou). He recites the Maha Karuna Dharani for years. And this is called real skill in cultivation. You may focus on one Dharma Door and will get the fruit. The only worry is that the laziness that stops you half way. Remember long-term continuous cultivation in Buddhism will yield fruit.