How to develop energy, rapture, tranquility and immersion? I am looking forward to develop 7 factors of enlightenment. The 7 factors of enlightenment are factors of mindfulness, investigation of principles, energy (viriya), rapture (piti), tranquility (passaddi), immersion (samadhi), and equanimity.
I have understood how to develop factors of mindfulness, investigation of principles and equanimity. 

However I am not sure how to develop the following:


Energy (viriya)  
Rapture (piti) 
Tranquility(passaddi) 
Immersion (samadhi)


(I guess Tranquility can be developed by becoming independent. If the answer to samadhi is to enter the first Jhana then my question will be how to enter it?)

So my question is: How to develop energy, rapture, tranquility and immersion? If you know answer to only one or few of the above factors then please post that as an answer. I will combine them.
There's a whole samyutta dedicated to the description and analysis of the Bojjhanga in the Connected Discourses (see Bojjhanga Samyutta). Also check out Ven. Piyadassi's great "Seven Factors of Enlightenment"